We have partnered with an incredibly exciting, fast-growing UK tax technology start-up that is rewriting the rules of the accountancy profession. Package of £85,000 with a 50% annual bonus + EMI Share Options Having already secured seed funding and currently progressing through a £1.5m round, they are building expert systems that transform incredibly complex tax legislation into clean, machine-readable code. Their platform is already live, integrated with Xero, and actively used by accounting practices supporting hundreds of SMEs. Up until now, the focus has been on flawless technical accuracy and functionality. Now, they need a Founding Product Designer to take complete ownership of the user experience and lead a ground-up redesign. There are no layers of bureaucracy, no endless sign-off processes, and no team to manage just yet. You will work directly with the founders (CEO/CTO) and sit face-to-face with users to turn a high-powered technical engine into a modern, intuitive, and genuinely beautiful B2B SaaS platform. The Role and Responsibilities As the solo design leader, you will be entirely hands-on, bridging the gap between complex backend data workflows and a seamless user experience. End-to-End Product Design: Own the UX/UI of the entire platform, including dashboard design, complex report builders, audit trail visualisations, and data ingestion flows. Build the Blueprint: Establish and maintain a scalable design system from scratch that the engineering team can buil