There are several reputable insurers and we have a topic that covers the subject. Why not browse there.

https://www.holidaytruths.co.uk/forum/travel-insurance-advice-recommendations-q-as-t1329-1080.html

You do not give your age or say if you have any medical conditions. Not wishing to pry but if you do then give us a little more information and some of our members may be able to assist. Thing to remember if anyone does hve a medical condition you are not on your own, others also have it.