Greenbee Travel Insurance is worth a look. UK based, provided by the John Lewis Partnership. Had policy for three years, claimed once for missed flights, paid without quibble even though the replcament ticket cost about five times the price of the original. Not too heavy a loading for pre-existing conditions either. Interestingly the last renewal quote was almost identical to the quote from Amex. I always check who the underwriter is as well and see if I get a warm feeling of reassurance when I see the name.