40+ Years of Experience,
Delivered Personally
We are a boutique tax and finance technology consultancy founded by two experienced professionals — with deep roots in Big 4 consulting, multinational in-house finance, and the leading tax technology vendors.
Boutique by Design
Osprey Consulting was founded with a clear purpose: to provide organisations with the quality of tax technology consulting found in the largest firms, but without the overhead, the complexity, or the lack of continuity that often comes with them.
When you work with Osprey, you work directly with us — Mark and Charlotte — from the first conversation through to completion. There are no handoffs to junior consultants, no account managers between you and your delivery team, and no time lost re-briefing people who were not part of your earlier conversations.
We specialise in tax and finance technology because it is where our experience sits — not because it is fashionable. Between us, we have implemented ONESOURCE Tax Provision and Corporate Tax across dozens of organisations, built Alteryx automation workflows that have transformed manual finance processes, and held senior in-house finance and tax roles at multinational groups.
"Delivering value from day one, without the overheads and complexity often found in larger firms."
— Our founding principle
Mark Hart
Co-founder & Director
Mark is one of the most experienced ONESOURCE Tax Provision specialists in Europe, with a career spanning Big 4 advisory, multinational in-house tax, and senior roles at Thomson Reuters.
Before founding Osprey Consulting, Mark held the position of Director of Solution Consulting at Thomson Reuters, where he led ONESOURCE implementation engagements across the UK and Europe. He has direct, hands-on experience with the platform across dozens of organisations and sectors — from initial design through to go-live and post-implementation support.
Mark qualified as a Chartered Accountant (FCA) and began his career at Arthur Andersen, before moving to Deloitte and subsequently into an in-house tax role at National Grid. He brings both the technical depth of a platform specialist and the commercial perspective of someone who has sat on the client side.
His particular areas of expertise are ONESOURCE Tax Provision configuration, ERP-to-OTP data integration, and the intersection of tax technology and Alteryx automation workflows.
Career Path
Charlotte Hart
Co-founder & Director
Charlotte brings over two decades of senior tax and finance leadership experience — across Big 4 advisory and in-house Head of Tax roles at a large UK multinational.
Charlotte qualified as both a Chartered Accountant (FCA) and Chartered Tax Adviser (CTA), beginning her career at Deloitte before moving into senior in-house finance and tax roles at a major UK multinational group, where she served as Head of Tax.
That in-house experience gives Charlotte a distinctive perspective: she understands what it means to own a tax function, to manage internal stakeholders and audit processes, and to have to justify technology investment to boards and finance directors. She brings this commercial grounding to every engagement.
Charlotte leads client relationships and engagement management at Osprey Consulting, and is particularly focused on process optimisation, tax function design, and ensuring that technology implementations are properly embedded in client workflows and teams.
Career Path
Our Approach
These are not aspirational values — they describe how we actually behave on every engagement.
Straightforward
We tell you what we think, not what you want to hear. If something is out of scope, unrealistic, or outside our expertise, we say so.
Accountable
We take ownership. There is no passing of issues down the chain — if something needs resolving, we resolve it.
Practical
Every recommendation we make is designed to be implemented, not filed. We think about your real constraints and work within them.
Collaborative
We work with your team, not around them. Knowledge transfer is a core part of every engagement, not an afterthought.
Trusted by Leading Vendors
Our partner relationships are long-standing and deep — not simply badged accreditations. We collaborate directly with Thomson Reuters, Alphatax, and Alteryx on client work.
Authorised ONESOURCE implementation partner. Mark is a former Thomson Reuters Director with deep platform knowledge across Tax Provision, Corporate Tax, and Statutory Reporting.
Partner relationship covering UK corporation tax compliance and automated return preparation. Products include Tax Proof and AlphataxCT.
Registered Alteryx Solution Provider delivering data transformation and workflow automation tailored to tax and finance functions.
Work with us directly
Every engagement is handled personally by Mark and Charlotte — not delegated, not scaled out. If you would like to discuss your requirements, we would be glad to hear from you.
Get in Touch