Multiple driver's licence expiry dates

I can't remember the purpose of the visit but recently I went into my high-street bank and needed to show my ID, which is pretty standard. I duly handed over my licence and after thoroughly examining it against my computer records, the teller pointed out with a hint of suspicion in her voice that my licence was due to expire in November 2010. I can understand why she would be confused, as licences in the UK are granted until one reaches 70. Thankfully I am nowhere near reaching that milestone, so it was a bit of a conundrum. There are two dates on the front of the card between the date of birth and the driver number, labelled 4a and 4b. There is a legend on the reverse of the card that describes 4a as "Licence valid from" and 4b as "Licence valid to".

Perfectly straightforward.

So why should my licence expire so soon whereas everyone else's lasts pretty much for life? Was it a mistake introduced by the DVLA when they last issued my card? As well as a 3-point deduction, was it part of the puninshment I receieved last year for being caught by a speed camera last year? Having convinced her that I was equally confused by the 'error', and that I was indeed who I was claiming to be, I completed my transaction and left the bank.

I called the DVLA. As soon as I mentioned "4b" (let alone the actual problem) the customer service rep interrupted me and gave me the answer. It was clearly a common question. It turns out that the "Licence valid to" isn't as described. This is the expiry date of the photo, not the licence itself. As we age and our features change, the photocards need to be updated. I tried to point out that the legend clearly implied the licence itself would expire and not the photo and that it was confusing. She clearly wasn't that interested in collecting such feedback so I pretended that I was satisfied with her answer, and no, there was nothing further she could do for me thank you very much.

Upon closer examination, there are more dates on the back of the photocard which I'm guessing are the 'true' "licence valid to" dates. These are in box "11", for which there is no legend entry, which is, let's face it, for the better.