We use a company called Columbus and take out annual holiday insurance each year, to date I’ve used them for 4 years and each renewal time they have been competitive, both my wife and I have more than one declared condition.
We inform them of any medical condition however major or minor, they then go through a yes/no questionnaire for each condition and so far so good.
We have been fortunate that we have not needed to claim, so you could say we don’t know how good they are……