I'm under 50 (just) and got some very good insurance from a company courtesy of Moneysavingexpert.com. I used
InsuranceWith who covered me for Rheumatoid Arthritis and Meniere's Disease for about £40 which isn't great but the 'included' options covered me for boat trips, surfing, paragliding etc lol. On a serious note, many people take holiday insurance and then don't realise they're *not* covered for these activities!
The information provided by the insurers they brokered for me was very good - simple and easy to understand. They even provide a letter/leaflet to hand to whatever medical professional you need to deal with in the case of an emergency, something I've never come across before. This takes a lot of pressure off you and your loved ones should something happen. They even had a team of interpreters to speak to the medical professionals. Well worth the additional premium I paid.
Hope that helps.