You could also try Go Compare, they will also give you a list of quotes once you have added your medical conditions. I have high blood pressure and got a reasonable quote for my holiday in May, I am returning in September so I contacted the same company again for a quote. This time they offered the same cover at double the price. It pays to shop around on more than one of these comparison sites.
Comparison sites will not give a quote as my friend only finished treatment for Cancer last year. Put in your details and they all call you with expensive quotes after going through laborious medical questions. There is a company that will insure her and I know somebody mentioned it in the past but cannot find the post.
After years of taking out travel insurance with same and different companies realised I was entitled to free cover with my bank when my salary was paid into account!! Since retiring only need to pay in a regular monthly amount from our joint account which together with state pension covers the minimum payin amount to continue with cover for free. I do have non serious pre existing conditions with medication. I believe several banks offer a similar service.