Update.
I now have the samples. The cap is a very generous size and has a neat adjustable buckle strap at the back that includes a place to tuck the spare length of strap (much posher than the usual plastic snap strip). Both cap and polo are pretty much exactly as the sample pictures already posted, but I'll take some pics of them tomorrow anyway. They were right about the sizing, it is pretty generous, at least the 'M' appears to be.
I'll post the final list of orders on 1st April (Tuesday). I'll place the order with the supplier a few days after that.
