Thanks for the reply
I'm neither in the US or the UK, so I'm going to have to assume I'm getting the UK keyboard (since that's what we have at work, and I'll be ordering through the same company) Since I can't order from the US store (they won't ship here), I might have to look into some other options...
The UK Apple Store (I know you're not in the UK) has an International English keyboard option which I suspect is the one you want. It's available as a stand alone product or as a BTO option. If your supplier is giving you British specced Macs he should be able to get an international KB. Worth asking.
Alternatively try Amazon. The pics on Amazon UK are confusing - the wired ones show the standard UK layout, but the wireless one has the layout you're looking for. I'm guessing that they just used a pic from the US store.
Amazon US will ship to you (or I'd be surprised if they didn't)
HTH