Given they share all claims information to stop multiple claims, they already have access to all the info they need.
This is the annoying thing about it. They can bloody access all the info that they need, but then ask you to dig out the proof.
I had an annoying situation quite a few years ago when I switched provider. They didn’t ask for previous proof of no-claims. I stayed with them for a couple of year and then when moving on they said they couldn’t provide me with proof of no-claims because I hadn’t provided proof of no-claims (that they hadn’t asked for) to them when I first took the policy out.
Eventually, they agreed to providing me with a certain amount of no-claims proof. I can’t remember how much now; something like 50% of what I actually had. Which just shows how preposterous the whole situation is, because they effectively just made my no-claims amount up on the spot….