i have just fiited another engine in my p38, it struggles to start unless i give it 3 turns of the key then turn it over, its as if it is the heater plugs but i have renewed these. any ideas would be appreciated.

If you're happy that your heater plugs are working, don't forget the relay, then it's fuel you're lacking. It could be the in-tank pump being weak not supplying enough fuel. If you've got a leak somewhere then you could be losing fuel pressure and again not enough fuel to start. Then you should check the leak-off pipes at the injectors.

Then get yourself into the Range Rover section where you would probably have had this info in minutes.