When we bought our 33 – from Dr Vic – he suggested that we should continue with the insurance company which he used, and we have done.
The company is Nautical Insurance of Leigh-on-Sea: https://www.nautical-insurance.co.uk
I haven’t COMPARED their prices, or their speed of response, or their payouts, etc, with any other company, and I’ve never claimed for anything. But they’ve always been helpful when I’ve wanted to alter the policy (..to add single-handed sailing, or extend the area of coverage, add a dinghy and outboard motor, etc..) and I think their fees are moderate – though I can’t remember offhand what they charge.
..Ah, here’s an old bill from 2014: Gross Premium £512.50. No Claims Bonus: -£128.13. Plus Insurance Premium Tax and Admin Fee; total: £427.43p.
Looks reasonable to me. Other views – and premiums – may differ!