All sorted now. Thanks folks. It was insurance that included wreck recovery I was after - not just stand-alone wreck recovery. And before anyone says that wreck recovery is/should/ought to be covered in any third party/fully comp insurance, I would remind you that insurance is a very precise art. One insurer might insure for something while another won't. And slight change to a boat's risk/circumstance will mean it is easier/harder; cheaper/more expensive to insure. Insurance for wreck recovery for a residential boat is regarded as quite different to that of a leisure or commercial boat. And a commercial boat that allows clients to take the boat out (a bareboat charter) has very different risks to one that doesn't (eg an AirBnB).
So if your assumption about insurance is based on your own experience of your boat or previous boats, best not to assume that my boat is the same or located in the same place or is used for the same purposes - all of which will affect the ability to insure and the price of insurance. Happy sailing.