Ewan
I think mine came within 2 weeks, but cant be sure as it was August 2008, so my memory is a bit fuzzy.
Best bet is to email them and ask, or call them.
In my case the diamond came from seattle, the ring was made up in Dublin and posted to me in Scotland. The prices on there are not inlcuding VAT, so you need to add UK VAT to the total. I dont thik I paid any import duties etc, it was all included in the price.
it still beats the high street prices by a mile!! and trust me that whatever you pay, the ring will be worth far more than that (provided you pick a good stone) :-)