Data Subject Acces: proof of phone no required

[Anwen11]

DS made subject access request for a transcript or, preferably, recording of a recent telephone conversation with a statutory authority. Advised that this is possible but that he would need to prove that the number he rang from is his. By, eg, providing a recent copy of of mobile telephone bill or evidence that he rang from the number recorded. If he had pay as you go, he'd need the receipt with the number on it.

He's with giffgaff which doesn't provide itemised bills. They'd need to provide proof of usage (if that were possible) because, other than that, he has no evidence that the phone number he rang from is his. Seems a bit odd as, after all, he could have rung from someone else's phone which would clearly not be in his name.

Is that how subject access works under the Data Protection Act 2018? Thanks for any suggestions.

Would you prefer that anyone could ask for a transcript without identifying themselves.

No, I wouldn't. But I was wondering how this can be managed given there aren't any phone bills as such or any other clear evidence of ownership of the number from which he rang.

Did the call contain information about him, or an account he owns? If so, can he offer to send them a passport/DL to proof his ID?

They are entitled to ask for evidence of identification to satisfy themselves that it is the right person asking for data, but it must be proportionate.