The biggest and quietest market is people already paying someone else to do their tax and payroll. They search "switching accountants" or "how to change accountant" because they feel unattended, not because they want to save money. Explaining how a handover works — professional clearance, records, timing — brings in clients who have already made the decision.
The other half are people starting up. They search with a different vocabulary altogether: company or sole trader, registration steps, first deadlines. They convert more slowly but stay for years if you get them through the first months.
Technical content is the strongest lever here precisely because your competitors avoid it. Deadlines and obligations explained in plain language rank for years, get shared between business owners, and position you as the practice that warns clients in advance rather than after the fine.
Client-facing services are searched separately too — payroll, VAT, year-end accounts. A page for each of them ranks for its own searches; a single "our services" list ranks for none of them.