Lead Network Engineer (Tier 3)

ARO; Liverpool; Hybrid; GBP 65,000 - 75,000; Full time

Job summary

ARO is seeking a Lead Network Engineer (Tier 3) in Liverpool to provide senior technical leadership across SDS-hosted NHS and public-sector networks. The role blends hands-on engineering with architectural oversight and incident management.

Based in Liverpool with hybrid work, you will mentor Tier 1/2, drive major incident resolutions, and contribute to security, resilience and service improvement across SDS data-centre and customer networks.

Qualifications

• 5+ years' relevant experience in senior network engineering, consultancy or technical delivery.
• Expert knowledge of enterprise routing, switching, firewalls and secure connectivity.
• Advanced experience with at least two core technology platforms, including Cisco IOS/NX‑OS, Fortinet FortiGate/FortiManager and Extreme EXOS/ExtremeCloud IQ.
• Advanced knowledge of BGP, OSPF, route redistribution, HSRP/VRRP, VLANs, spanning tree, MLAG and 802.1X.
• Strong understanding of firewall policy, NAT, VPN, segmentation, SD‑WAN and resilient network design.
• Experience supporting complex, multi‑site and data‑centre networks underpinning business‑critical hosted or managed services.
• Proven ability to lead major incidents, complex changes, migrations and technical problem investigations.
• Experience producing and reviewing technical designs, implementation plans and supporting documentation.
• Strong understanding of ITIL‑aligned incident, problem, change and service‑transition processes.
• Ability to work independently, exercise sound judgement.

Responsibilities

• Act as the Tier 3 escalation point for complex incidents, problems and technical risks affecting SDS-managed networks and the customer services they support.
• Take end-to-end ownership of escalated SDS issues, ensuring accurate records, regular communication and timely resolution.
• Lead the technical response to major incidents affecting SDS-hosted and managed services, working with customers, vendors and internal teams to restore service safely and promptly.
• Troubleshoot complex LAN, WAN, WLAN, firewall, VPN, SD-WAN and data-centre networking issues across the SDS service estate.
• Work with the Principal Network Engineer to implement SDS technical standards, architectures and technology roadmaps.
• Produce and review technical documentation, including high/low level designs, implementation and migration Plans.
• Provide technical assurance for new SDS solutions, customer onboarding, migrations and high-risk changes.
• Lead complex SDS network deployments, data-centre changes, customer cutovers, upgrades and transformation activities.
• Review and approve technical plans produced by Tier 1 and Tier 2 engineers.
• Lead root‑cause analysis and ensure permanent corrective actions are identified and delivered.
• Support capacity, lifecycle, vulnerability, firmware and technical risk management.
• Improve monitoring, resilience, security, automation and operational efficiency of SDS-managed network services.
• Ensure new/changed SDS services are documented, monitored and transitioned into operations.
• Maintain relationships with SDS customers, colleagues, partners and vendors across NHS/public-sector environments.
• Mentor Tier 1/2 engineers and contribute to development plans.
• Maintain current technical knowledge and complete vendor/industry accreditations.
• Support planned out-of-hours activities as required.

Skills

Senior networking

Cisco IOS/NX-OS

Fortinet FortiGate

Extreme EXOS

BGP/OSPF

VPN/SD-WAN

ITIL processes

Tools

Cisco IOS/NX-OS

Fortinet FortiGate

Extreme EXOS

Job description

Job Title: Lead Network Engineer (Tier 3) Location: Liverpool (Hybrid) Salary: From £65,000 Contract type: Permanent #LI-Hybrid

About the role

ARO's Specialist Data Services (SDS) business unit is seeking a Lead Network Engineer (Tier 3) to provide senior technical leadership across the resilient data-centre and customer networks underpinning SDS-hosted NHS, clinical and public-sector services. Working closely with the Principal Network Engineer, you will translate SDS technical strategy and architecture into secure, resilient and supportable solutions. You will act as the senior network escalation point for Tier 1 and Tier 2 engineers and lead the resolution of SDS's most complex incidents, problems and technical risks. This role combines advanced hands-on network engineering with technical assurance, design review, mentoring and continual service improvement across SDS-managed data-centre, wide-area and customer network services. The role's primary remit is the SDS service estate, including critical NHS, clinical and public-sector services delivered from ARO's Liverpool and Runcorn data centres. You must be comfortable operating within structured environments aligned to ISO 27001, NHS DSPT and ITIL practices. The role is predominantly based within the SDS NOC in Liverpool, with home-based working two days per week and occasional attendance at the Runcorn data centre and customer sites to support operational or project needs. Please note this is a hybrid role based out of the Liverpool office 3 days a week, with 2 days working remotely and occasional attendance at other sites as required. You must be able to commute to these locations and have your own transport.

What you'll do

Act as the Tier 3 escalation point for complex incidents, problems and technical risks affecting SDS-managed networks and the customer services they support.

Take end-to-end ownership of escalated SDS issues, ensuring accurate records, regular communication and timely resolution.

Lead the technical response to major incidents affecting SDS-hosted and managed services, working with customers, vendors and internal teams to restore service safely and promptly.

Troubleshoot complex LAN, WAN, WLAN, firewall, VPN, SD-WAN and data-centre networking issues across the SDS service estate.

Work with the Principal Network Engineer to implement SDS technical standards, architectures and technology roadmaps.

• Produce and review technical documentation, including:
  
  
  
  • high-level and low-level designs
  
  
  • implementation and migration plans
  
  
  • test and validation plans
  
  
  • rollback procedures
  
  
  
  


• Provide technical assurance for new SDS solutions, customer onboarding, migrations and high-risk changes affecting hosted or managed services.


• Lead complex SDS network deployments, data-centre changes, customer cutovers, upgrades and transformation activities.


• Review and approve technical plans produced by Tier 1 and Tier 2 engineers.


• Lead root‑cause analysis and ensure permanent corrective actions are identified and delivered.


• Support capacity, lifecycle, vulnerability, firmware and technical risk management.


• Improve the monitoring, resilience, security, automation and operational efficiency of SDS-managed network services.


• Ensure new and changed SDS services are documented, monitored and successfully transitioned into the SDS operational support model.


• Maintain effective professional relationships with SDS customers, colleagues, partners and vendors, particularly across NHS, clinical and public‑sector environments.


• Mentor Tier 1 and Tier 2 engineers and contribute to individual and team development plans.


• Maintain current technical knowledge and complete agreed vendor or industry accreditations.


• Support planned out-of-hours activities affecting SDS customer services and data-centre platforms where reasonably required.

What we are looking for?

Essential 5+ years' relevant experience in senior network engineering, consultancy or technical delivery, ideally within an MSP, ISP, data‑centre provider or similarly critical hosted‑services environment.

Expert knowledge of enterprise routing, switching, firewalls and secure connectivity.

Advanced experience with at least two core technology platforms, including Cisco IOS/NX‑OS, Fortinet FortiGate/FortiManager and Extreme EXOS/ExtremeCloud IQ.

Advanced knowledge of BGP, OSPF, route redistribution, HSRP/VRRP, VLANs, spanning tree, MLAG and 802.1X.

Strong understanding of firewall policy, NAT, VPN, segmentation, SD‑WAN and resilient network design.

Experience supporting complex, multi‑site and data‑centre networks underpinning business‑critical hosted or managed services.

Proven ability to lead major incidents, complex changes, migrations and technical problem investigations.

Experience producing and reviewing technical designs, implementation plans and supporting documentation.

Strong understanding of ITIL‑aligned incident, problem, change and service‑transition processes.

Ability to work independently, exercise sound judgement