We bought the ones that zip up for the kids, if those are the type you mean Dave. Similar (but zippier) than these:

They were very good quality, snug fit and we bought them in one of the trendy looking shops around the new silver building that backs on to Paspatur in Fethiye (the one along from Burger King).
I don't know how much they were (other than not excessively expensive) or whether you could buy cheaper in UK, but we were happy with them.