Thanks for your replies but unfortunately we bought a full years travel insurance in February before I was diagnosed.
My hubby has had serious health issues and we found this company last year as they really were the cheapest with the best cover. We had been quoted from £300 to £700 last year from various companies when we went to USA and we got cover through this company for £150 for single trip cover.
Asked for quote from the company in Feb when I didn't have diagnosed problems and cover was this year £160 for annual cover which we bought. I think I am just going to have to contact the company again and back it up with documentary evidence that the CPAP is a vital bit of kit and not something that is going to go away! From their point of view I would have thought that it is good I am being treated with CPAP and should not make any difference to the cost of insurance.
If I have to pay extra I suppose it's still cheaper than other quotes anyway