I tend to view the photo-licences as a bit of a farce I'm afraid.
There seems endless confusion about which part matters most - the pastic card or the A4 paper sheet that comes with it. When I was in a major crunch a while ago the attending police were, actually, satisfied with just the plastic part, which was lucky as I don't always carry the paper part. Conversely, when I get my car serviced, it's the paper part I need to show the garage in order to get a loan car.
I suspect that, actually, the police already had every minute detail of my entire driving history on their computer systems, and what they really needed was proof of ID, which the card provided. Wheras the garage are less interested in proof of ID but simply need to know if I have umpteen points on my license before lending me their car.
Great system, huh?