Train carriages in wrong order...

I've been getting the 9.07 (Walton) train every morning for 11 years. For the last 4 years I have been commuting with a folding bike. I always get on at the same place, 1 carriage after the middle first class carriage.

For the last couple of months, every so often, instead of the usual carriage, the First Class Carriage turns up. Why are you suddenly messing up the order of the carriages?