[Notspot]

Think what you really need is someone from overseas (not in UK) who has set up a UK Ltd company. If you're already registered for tax in the UK it's very easy and cheap but I think there'll be complications for overseas companies that we UK folks won't be aware of.

I've got some bookmarks of URL's of useful resources / companies that I have used - I'll PM them to you if you're interested, but I think what you're after is more specialised and I've taken a quick look at them and they don't mention overseas clients.