I agree 100% with Woozer - it's very important that you get the right advice. For example, there is a huge difference between Personal Accident & Sickness Insurance on the one hand and Permanent Health Insurance on the other. The latter is more expensive but gives you much wider cover.
Make an appointment with an Independant Insurance Broker or Financial Adviser and make sure that you fully understand what the options are. Don't try and buy this sort of cover on line - you need advice!