I need cover for two weeks in Tobago to include scuba diving up to 40m (I’m qualified!). The best I’ve seen so far is £65. Has anyone found anything better?

I just did a quotation for you from http://www.travelinsuranceweb.com based on the details above. They have a selection for scuba diving upto 50m. It came upto £23.69 with the full cover you would expect from travel insurance for this kind of activity. Check it out.