Accounts Payable Assistant

£30-34k / Hybrid - London

IONATE is a deep-technology scale-up building the technology backbone for smart electricity grids. Our London team is looking for an Accounts Payable Assistant to support the Finance function on a full-time basis.

Requiring solid purchase ledger experience, you will work closely with our AP Supervisor and Financial Controller, supporting our UK and Austrian entities. You will play a key role in keeping the purchase-to-pay cycle running smoothly, ensuring suppliers are paid accurately and on time, and that records are clean and audit-ready.

This role focuses on delivering the day-to-day accounts payable function while helping us improve and document processes as the business scales. You’ll work with colleagues across the company to streamline approvals, strengthen controls, and maintain high-quality data in ExpenseIn and Xero (multi-currency).

What you will do:

• Own the end-to-end AP process: invoice capture, coding, approvals, posting, and payment
• Be the first point of contact for supplier and internal AP queries; resolve discrepancies promptly and professionally
• Process purchase invoices and credit notes in ExpenseIn and Xero (including multi-currency), ensuring correct VAT/tax treatment where applicable
• Manage employee expenses and company credit card transactions, ensuring policy compliance and accurate coding
• Maintain the purchase order process: ensure POs are raised for committed spend, obtain approvals, and match PO to invoices
• Prepare weekly payment runs and ad-hoc payments, ensuring payments follow approval controls and agreed supplier terms
• Reconcile supplier accounts and statements; investigate and clear aged items, duplicates, and unmatched transactions
• Perform bank reconciliations and support month-end close activities related to AP
• Manage the Finance shared mailbox, prioritising queries and maintaining clear audit trails
• Support onboarding and maintenance of supplier master data (e.g., bank details) in line with internal controls
• Manage HMRC customs reporting requirements and payments relating to import taxes on supplies
• Provide reporting and supporting documentation for financial reporting and audit requests, and contribute to continuous improvement initiatives

Requirements

• Proven experience in a purchase ledger / accounts payable role, with a good understanding of the end-to-end AP process
• Experience working in a small, fast-paced team
• Exceptional communication skills
• Excellent attention to detail and a high level of accuracy when processing transactions
• Strong organisational skills and ability to prioritise workload and meet deadlines (including payment run cut-offs)
• Experience processing invoices, expenses, and payments
• Confident using accounting systems (experience with Xero is required)
• Intermediate Excel skills (e.g., pivots, lookups) and comfortable working with numerate data
• Professional, helpful approach to stakeholder and supplier query resolution

It would be useful to have:

• Experience with ExpenseIn (or another expense/invoice workflow tool)
• Exposure to multi-currency processing and/or import duties and customs documentation

Benefits

• Employee Option Plan: You get equity in IONATE, so as we succeed so do you.
• Private Medical & Dental Insurance: From day one, we provide you with full, comprehensive private medical and dental cover through Bupa. You also have the option to add any dependents to your cover. Please ask us for more details.
• Company pension: a flexible, and sustainable pension product to help you plan for your future.
• Career Development:  It’s important to us that you have the opportunity for ongoing professional development and career growth. You will receive an annual budget for professional development and work with your team to set and reach goals every year.
• Flexible working schedules: You will be based in our modern West London offices 3 days per week and will have the flexibility for hybrid work-from-home arrangements. Talk to us at the application process about this.
• Cycle to Work Scheme: Low carbon travel is important for everyone, so we have in place a cycle scheme to help you purchase a bicycle.
• Slow travel: We believe in a low carbon future, so if you wish to travel by a lower carbon method – but it takes much longer than flying - we will give you an extra 2 slow travel days per year.