Health insurance after cancer

Hello I've had prostate cancer and skin cancer in the last 2 years as well as a hip replacement and am about to take voluntary redundancy at 61. While employed I was lucky enough to have BUPA which covered my treatment but this will end when I retire. I asked BUPA for a quote to extend and it was ridiculously expensive, which wasn't a great surprise. Does anyone have recommendations of other more affordable providers? Thanks!