Yeah i spoke to motorsport development they do not do them anymore, (even though they are still on their website!!), which is a shame becaue they did have a built in adjustable pressure switch and were only £125!

Whats wrong with a pressure switch?
Doesnt it just need to switch the injector on at a certain boost pressure, for a ceratin duration, to enrich the mixture? This is set by the tuner on the RR.
This is what it my tuner told me and also what it says on the MD website.

Karlos