Re: WTF..?
Driving licence numbers will have been harvested from people trying to get car insurance quotes and passed to equifax for insurance fraud checking, and that will be their excuse for keeping it until year infinity + 1. I notice the usual suspects on the price comparison websites tempt you into giving driving licence numbers for "better quotes."
An example needs to be made of Equifax. I think the last 10 years of their UK subsiduaries' profits is a good starting figure for a fine for criminal negligence, ought to bring the risk-reward ratio into the realms of reality, rather than the current situations of no risk, all reward for profiteering from our data.