Stopped using banks for house insurance over 20 years ago when Margaret Thatcher stopped the company used being compulsorily tied to your mortgage and a nameless bank something along the lines of twitwest quadrupled my house insurance quote where the insurance company had suffered big losses elsewhere. Rarely will a bank offer anything better than very poor value for money IME.
Personally, I think the difficulty in ending auto-renewal car/house/etc insurance is something that the FCA should act on with firm guidelines as some poor insurance companies exploit this. I had a problem with a big insurer along the lines of liedential who just kept ignoring my cancellation requests and then threatened to take me to court after I cancelled the DD, to which I replied, yes please, so I can expose your shoddy tactics. I never heard anything more after that.