The problem is, how do we know which is a good company with regards to claims?
Are there any web sites out there that list good and bad ones?
Its not easy specifically to claims, but this is a start as far as looking at the product as a whole.
https://www.defaqto.com/star-ratings/motor-insurance
Re claims specifically the only way to work out what companies are good is word of mouth and asking lots of the correct questions (and having someone within the company who knows what they're talking about answering them).