DTUK make import both a tuning box and a pedal box.
... corrected that for you.
They import them from DTE in Germany.
and have done since 2005 
Whilst you are here Andrew - have you any observations on using your tuning box with premium diesel? I accidentally picked up the Premium Texaco nozzle the other day, so just went ahead and filled the tank. It honestly felt like another 20bhp had been added to the car, and I don't think it was placebo as I had forgotten all about it until I noticed the car was picking up much faster than normal.
I normally add Millers EcoMax to each tank, but I've never felt the car drive like this.
Also - nice dyno's Finglonga, I've used 2+2 for a long time, would have been interesting to see a +2 vs a +3 too! I can also recommend adding a pedal box if not already.