K12 Non starter

Hi all, I replaced the gearbox in 2005 k12 1.0 Lt SX, Car drove fine for about 20 minutes, got back home , the car started to lose power and stall, after 5 minutes car started again drove fine for 10 minutes and i parked it, 3 hours later decided to head out again and the car was way down on power, drove less than a mile and the car stalled, towed it home, checked plugs, checked all connection's, plugged the car in 10 faults show P0340 C
Cam Sensor,P0223,P0222, P0123, P2135, P0302, P1610, P0113, P0444, P0107, Cleared all faults car still won't start, plugged car back in 4 faults P0107,P1611, U1001,P0113CLEARED still not starting, plugged back in 2 faults p161, p16ff after clearing these the car started for about 10 seconds before cutting out, checked all fuses and trid spare key still wouldn't start, immobiliser light on dash goes out as normal, any help appreciated
Are there any earth straps on the gearbox that have been left off or need cleaning.
If the car was ok before fitting the gearbox then that is the only thing I can think that would cause the issues