Here are some mileages for some of the former 555 SN16s and the CNL YX68s:-
10552-8 are Barrow based, 10559 is Kendal, 10560-3 are Morecambe based.
10552 - 514,199
10553 - 468,558
10554 - 507,571
10555 - 532,527
10556 - 522,867
10557 - 510,192
10558 - 497,120
10559 - 473,114
10560 - 468,228...