i remember before PIP a few times when i when to order a a car dealer would not accept a letter from mobility (dwp) confirming i had DLA they said you need the original letter, im 53 know and got DLA (or what it was called at that time ) when i was 16 , i did look out the original lettter but it was it a bit of a state the writing was all faded paper was falling to bits over the years , i phoned mobility (dwp) and got a confirmation letter from them that would do . some dealers can be very particular.
i should look out my original letter now and see if there’s anything left of it