Assistant Management Accountant

On Device Research Ltd; Greater London; On-site; GBP 30,000 - 42,000; Full time

Benefits offered by this job

Hybrid working

25 days annual leave

Birthday day off

Job summary

On Device Research Ltd is seeking an Assistant Management Accountant to join a small, supportive finance team in London. The role starts with AP/AR processing, reconciliations, and bank reconciliations, then grows into month-end production as automation increases. You will be supported to study CIMA/ACCA and become proficient in Xero and Excel.

The position offers hybrid working, two days in the office weekly, and a path toward management accounts production with FD support.

Qualifications

• Studying CIMA or ACCA — any stage, with full study support.
• 1–3 years experience in a finance role with hands-on Xero.
• Confident with AP and AR end-to-end, including credit control.
• Willing to be in the office at least two days per week.
• Strong Excel skills and ability to build tidy working files.

Responsibilities

• Month-end support: reconciliations, journals and inputs.
• Post month-end journals (accruals, prepayments, depreciation, payroll).
• Own balance sheet reconciliations for FD review.
• Prepare monthly sales commissions report for FD review.
• Grow into more month-end production as automation increases.
• Maintain Excel models: cash flow, aged debt, AR/AP reports.
• Produce weekly AR/AP reports for FD, highlight cash impact.
• Support ad-hoc commercial analysis for FD/CFO.
• Respond to budget holder queries with FD oversight.
• Own AR: raise invoices in Xero, allocate receipts, credit control.
• Own AP: enter supplier invoices in Xero and run payments.
• Manage shared accounts inbox; assist with queries.
• Reconcile Xero bank accounts and review auto-rec tool.
• Help automate transactional and reporting work; document processes.

Skills

AP/AR end-to-end

Credit control

Strong communication

Organised and proactive

Teamwork

Education

Pursuing CIMA/ACCA (any stage)

Tools

Xero

Excel

Job description

Company: On Device
Position: Assistant Management Accountant
Location: London Office/Hybrid
Work Pattern: Monday to Friday 9.00am - 6.00pm

About the company

On Device is a Brand Lift Measurement company for advertisers, planners and publishers. Our cross-media measurement system makes every aspect of brand advertising accountable through dissecting campaign performance to reveal the truth on brand advertising effectiveness. Partnering with leading brands, ad agencies and media owners, the company has earned recognition through various awards for its exceptional work, including Best Companies to Work for in 2023 and 2024.

About the role

On Device Research is looking for an Assistant Management Accountant to join a small, supportive finance team. The team consists of the Finance Director, this role, and a Fractional CFO who works one day per week. You will report directly to the Finance Director.

This is a mixed role in a small team. In the first 3–6 months you will spend roughly half your time on AP, AR, the accounts inbox and bank reconciliations. The Finance Director continues to produce the monthly accounts during this period while you learn the business and the ledgers. Over the following months, as transactional work is automated, the time spent on Finance Assistant work drops, with you taking on more of the month-end production.

It is a great opportunity for someone studying CIMA or ACCA — at any stage from just starting out to part-qualified — who wants real ownership of ledger work, exposure to month end, and the chance to grow into management accounts production. We will fully support your continued study.

Specific responsibilities

Month end

• Supporting the Finance Director at month end with reconciliations, journals, and inputs. The FD will continue to produce the monthly accounts for the first 3–6 months while you settle in.
• Posting standard month-end journals under FD direction: accruals, prepayments, depreciation, payroll, and similar.
• Owning balance sheet reconciliations (control accounts, accruals, prepayments) for FD review.
• Preparing the monthly sales commissions report for FD review and payment.
• Over time, taking on more of the month-end production currently done by the FD as your confidence and the teams automation grow.

Analysis and reporting

• Maintaining a small set of Excel models, including a cash flow tracker, aged debt analysis, and the weekly AR/AP reports.
• Producing useful weekly AR and AP reports the FD can act on (cash impact, ageing, queries, risk items).
• Supporting ad-hoc commercial analysis for the FD and Fractional CFO.
• Helping respond to budget holder finance queries with FD oversight.

Accounts receivable, accounts payable and the accounts inbox

• Owning AR end-to-end: raising sales invoices in Xero, allocating receipts, credit control, and aged debt management.
• Owning AP end-to-end: adding supplier invoices to Xero with clean coding and supplier setup, and preparing payment runs for FD approval.
• Managing the shared accounts inbox for AR and AP queries.

Bank reconciliations

• Owning Xero bank reconciliations end-to-end, including managing the auto-rec tool and applying judgement on coding and exceptions.

Controls, automation, and improvement

• Helping to tighten day-to-day finance controls (approvals, coding, supplier setup).
• Leading the automation of transactional and reporting work — finding ways to reduce manual effort and free time for management accounts work.
• Identifying and leading improvements to Xero workflows and reconciliations.
• Documenting finance processes so the team has a single source of truth.

The ideal candidate will have

Essential

• Studying CIMA or ACCA — any stage from just starting out to part-qualified. We will fully support your continued study.
• 1–3 years experience in a finance role, with hands‑on experience of Xero or a similar accounting system.
• Confident with AP and AR end‑to‑end, including credit control and managing supplier and customer queries.
• Eager to grow into management accounts production over time, with FD support.
• Solid Excel skills: comfortable with pivot tables and building tidy, well‑structured working files.
• Strong written and verbal communication, including for managing a shared accounts inbox and engaging with non‑finance colleagues.
• Accurate, organised, and able to manage your own workload across transactional and management accounting tasks.
• Willing and able to be in the office at least two days per week, and proactive in building working relationships with budget holders and colleagues outside finance.
• Approachable, willing to learn, and willing to help.
• Embraces AI: willing to learn and adapt to new AI models and tools, and to apply them to improve how finance work gets done.

Desirable

• Experience working in a small finance team where you have owned tasks end‑to‑end.
• Some exposure to month‑end inputs, reconciliations, or commercial analysis.
• Familiarity with automation tools, dashboards, or AI workflows in a finance context.

What can we offer you

• 25 days annual leave
• Day off for your birthday (or can be switched for wedding or moving house)
• An additional day’s holiday for each year of service to a maximum of 30 days
• Sabbatical after 5 years’ service and 10 years’ service
• BUPA health cash plan, including dental and eyecare
• Bike to work scheme
• Season travel ticket loan
• Remote working in a different location
• Flexible/Hybrid working
• Access to our London office
• Contribution towards home office (separate from laptop/IT equipment)
• Regular company socials
• Enhanced maternity and paternity leave
• Early Friday finish during the summer months
• Bonus scheme (target dependant)
• Annual salary reviews (discretionary)
• Team lunches and work anniversary lunches
• Training programme in place for all employees

On Device is an equal opportunities employer and there shall be no discrimination to any candidates based on age, disability, sex, race, religion or belief, gender reassignment, marriage/civil partnership, pregnancy/maternity, or sexual orientation.

We recognise that diversity encourages better business and as such, we actively promote equal opportunities at all levels. We welcome all applications from a wide range of candidates. Selection for roles will be based on individual merit alone.