I really don't think I'm that small, but I gained weight (15-20 years ago) then lost it, mostly (5-10 years ago) and now appear to be a size 10 in trousers in some brands, which I wasn't of course before (vanity sizing).
I'm 5 ft 3, just over the overweight line (have a little more to lose I know), waist is quite big for the rest of me, most of me is the same height as someone who is taller except my lower legs.
So I tend not to buy petite clothes, I generally buy regular and take them up a bit if I need to.
I'm currently wearing a Boden 10R pair of trousers and they are not tight round the waist at all. They do go down to 6 I think.
In store at Next they only seem to go down to 8 and I also have found size 10 loose sometimes.
So where do you shop if you're 5 ft 3 and not overweight?? It's right on the top end of petite height and I can't be the only one who isn't the right proportions for petite.