I understand that Edward William have folded because their backers, Northern Reef have gone belly up. If not, please let this forum know.
The way I see it is that you need to take out a separate insurance to insure against your primary insurer from folding. To have paid premiums only to discover that it has been an exercise in futility is really not good enough.
When insurance companies fold (and they do, regularly, or suddenly change the rules) then you will be amazed to discover you are up s..t creek.
e.g. I understand that Panatelus (?) has suddenly decided they won't cover plywood
hulls. Does that include all those hulls with glass over plywood