OK, thanks guys
New pedal box arrived today. Very well built but heavier than claimed. Website says 2.8kg but it is a little over 3.4Kg
However, there is a lot of scope for lightening so I will attack it over the next couple of weeks.
Dry fitting box confirmed that it has to be recessed into the floor. I will also see if I can move the bulkhead/wheel well forward 20-30mm.
Modified master cylinder reservoir (shortened and lightened)) fits but was a little high so I reduced length of fitting. Every little helps. I will be replacing them with aluminium ones as soon as my 5/8" die arrives
However, there is no guarantee that the reserviors will remain where they are. It depends on how they interact/interfere with my feet.