So. Having read this thread and recently done my annual 'stock-check' to prepare a big order for the coming year, I decided to compare the general costs of items from different suppliers.

The upshot is, the same order will cost me approx. 100GBP LESS (including shipping) if I order it from the US, rather than sourcing it here in the UK.
To boot, there's a couple of items that I can't seem to find in the UK that I can get from overseas (namely bulk 35mm Tmax100).

I've read in the linked thread that customs and import charges will be added when the item is landed in the UK. (Surprise surprise HMRC want to fill their pockets with even MORE of my hard-earned!)

My question is this: how are these charges calculated and when (and to whom) do I pay them?

Or more simply... other than what I pay to Freestyle, what else will I need to pay?