I didn't no, but then I didn't' have the previous set from new (they must have been 6 months old when I brought the car 3 years ago) so I don't know how many miles they had on them in total. I put ~20k on them. Rears were evenly worn with around 3-4mm left on them - the issues they had were cracking (inside the main tread rings) and a few gashes. Fronts were also pretty decent, around the same left on most of the tyre apart from the outside edge which was really scrubbed. They were Bridgestones and I've gone to Dunlop now for a change.
Personally I think the old tyres would have been ok for another year but the MOT testing centre (don't know if you guys have a similar annual roadworthiness test) insisted on failing it. I think they were hoping I'd just pay them for a new set of tyres but I specifically did not as I don't want to support that model of business generation
Thanks for all of your help ard. I'm surprised you don't have a sticky thread with all of this info in it.