Here you go, snap this one up.
http://www.ebay.de/itm/Audi-A8-S8-D2...item2a199db66b
Then all you need is a clutch pedal and over-center spring.
Although it is a slightly different part number on VagCat. Hopefully not too different, definitely there is space and the mounting shaft for the clutch pedal.
doh! sorry just realised you already have a LHD pedal box
Just have a quick look at your pedal box to see if it has the master cylinder mounting recess and the over-centre spring brackets.
Here is a picture of how it should look. The ebay picture seems to have at least one of the over-centre spring brackets.