Another vote for Insurancewith.
Medical insurance is a either a blatant rip-off, a minefield, or both; especially if you need coverage in the US or Spain. I wanted coverage for my wife and me to visit Prague, and Venice later in the year. We both have medical conditions that could not be accepted on-line, and so I had to speak to someone.
One company quoted over £3,500 for these two trips and £1,750 for the Prague trip only. Insurancewith, were a more realistic £85 for Prague and £89 for Venice, because it is a five day, rather than a four day visit.
The agent said that in most cases involving medical conditions, it is invariably cheaper to buy insurance per visit rather than multi-trip. The risk profile is more favourable to the underwriters apparently.