Norwich Union --> Aviva

I may be mistaken, but the impression I gained from their publicity is that there has simply been a change of name, and accordingly there can not have been any transfer during which records could have been lost.

So if your records were lost, it may just have been "one of those things which happen occasionally" and nothing to do with the change.

Alternatively, your claims dept contacts were just saying they had no record of your property being *currently* insured, and you didn't quite manage to get the message across that your matter concerns an old claim under a policy no longer in force.

You do presumably still have the original policy documents, so there can be no question of lack of proof. Whatever you do, don't part with the originals. Send them copies.