I used comparison websites to get an idea of the range of prices, and what those prices covered.
Having sorted some likely insurers, I would contact them directly, to clear any questions, and make a deal direct with the insurer.
For roughly the last 20 years, I used the same insurer but I still did an annual check with comparison websites, this left me able to say, " the same cover can be had for £x can you match it," they did!
The trick was to ask questions of the Indian call centre that forced them to hand me over to a UK office.