Jen, totally agree, sizes have changed so much. If you look on different clothing websites, eg next, M&S at their sizing guides, you will see they all have completely different definitions of a size 14! Its rediculous!
Even within one shop, their sizes vary a lot. I tried on 2 pairs of jeans in next yesterday (next in forestside Kei - you are in Belfast, aren't you?!) One pair fitted fine, the other pair wouldn't even close!