[YorkshireT]

You don't need any DVLA code for any hire - I hire regularly in US, Spain, Ireland, Portugal. Never been asked for it.
It is another case of ridiculously planned out system for data protection, but in this case it was so bad, it worked in the customers favour, as the hire companies realised their business couldn't function if they insisted on it, so basically abandoned all pretence of checking for previous convictions.