I have never had trouble with travel insurance before, as was insured with what seemed like a rather generous company who didnt even charge a premium for my moderately severe asthma! However they don't seem to be doing new policies this year for some reason and I was disappointed to find that the suggested replacement company wouldnt cover my asthma at any price, even though I have had no admissions in the last year and am really rather well at the moment - so am not really too bad an insurance risk!
I was in a bit of a flap as am going to the channel islands on Sunday and only just found out they are not part of the NHS! I searched on here and found suggestion to try Freedom Insurance, who couldnt have been more helpful and have covered me and my (healthy) partner for 268 pounds, worldwide, for a year. This is more than I have paid before but seems eminently reasonable.
So I can definitely endorse Freedom (they have a website under Freedominsurance) - others with much more severe asthma than me have also had success with them.
Just thought I'd share something good, after a morning of panicking!