Not Starting/ Rough Idle after head gasket and timing change

[11esprit]

I was wondering if someone can help. The timing belt slipped on my 2008 407 2.0 hdi 140 so my local garage replaced all valves, rocker arms, new head gasket and timing belt which was all lined up. It briefly started after replacement but had a very rough idle, after this it is refusing to start. The injectors are working and getting voltage, hp pump fine and ecu and fuse box has been checked and all fine but it still refuses to start. It will only start on easy start but switches off as soon as no easy start is used. Mechanic believes timing is correct as there is compression but he has not done a gauge test on each cyclinder also is it possible he has got the valve timing slightly incorrect or would it more likely be an electrical issue such as injectors losing there programming or immobilizer. I appreciate any responses thoughts on this.

[Old Merc]

Why are you getting involved? you're paying this garage to sort the engine out.It should be them asking advice they have obveously cocked up somewhere and need help.Or have you picked the wrong garage?

[11esprit]

I think they are decent garage, have been using them for 10 years. Even the head mechanic is a bit perplexed and has re-checked his work but cannot find the issue. He is thinking it is an electrical issue.