@AC Sorry I disagree on this. I appreciate this is your job and not mine but my experience differs. I bought an iPhone from Apple direct; they offer AppleCare+ (clearly an insurance product) and I wasn't asked to complete/sign any form stating I'd been offered insurance nor that I'd declined that offer (I didn't buy AppleCare+). I also bought an iPhone from John Lewis*. They didn't get me signing forms for any reason (insurance or otherwise) they reserved it over the phone (with only my phone number, no account or payment required) and when I went to the store they took my money and gave me the sealed iPhone box like the OP expected CPW to do.
Frankly, this smacks of the overzealous implementation of a simple regulation into overly complicated store policy. If the FCA requires this a citation of the regulation would be useful. Really, this form screams data harvesting operation to me.
*I bought an iPhone SE shortly after Apple discontinued them back in September. I called my local Church of Jobs asking if they still had stock left. They did but the guy I spoke to told me to try JL first as they were selling off their stock for £100 cheaper which he couldn't match. Apple get a lot of criticism (plenty of it justified) but I can't fault that kind of service!