Phil, I assume if it's an underfloor set-up you've got the lines installed in the M/C correctly?
You seem to have covered all the other bases.
Bear in mind if it is underfloor, the M/C is reversed relative to its original position on a firewall.
Is it possible Fatman have sent you a disc/disc M/C?
AFAIK discs require much less volume of fluid to operate.
The front circuit should activate slightly before the rears as they do most of the braking.