My garage roof and sidewall have now big gaps in it, everything is ruined in my garage, this could have been caused by the erection of a new Morrison Building next door, have asked the Management Company and they have said its not down to them and no.

Depending on how close to you the morrisons building was you might have been supposed to be protected by the party wall act procedures. I'd start by sending photos and threat to Morrisons. Yes you could get the buildings insurance involved, but probably to be covered they'll be looking for a single event as the cause/accident to pay up.

Mr A Williams,