Hello, I hope the following is of assistance.
As the engine fires on easy start then this is a fuel concern, although there is diesel at the injectors it won't be under enough pressure to start the engine. The most common concern of this type is a fault with the fuel pump or its wiring.
If you have access to a diagnostic scanner then use this to retrieve any fault codes stored in the PCM, this would confirm if it is a pump problem. If you don't have access to a scanner you can check the pump wiring but obviously if it's not a pump fault then you will find it all checks OK. Start with checking the fuses for the pump, these are in the fuse box under the bonnet and are at the top both 20 amp. If these are OK then check the wiring to the pump, make sure it isn't damaged where it runs near the inlet manifold and starter motor. With the pump connected and the ignition on pin 7 is a 12 volt feed pins 6 is earth, pins 1 and 2 are CAN wires, try disconnecting and reconnecting the pump connector as sometimes it can be a poor connecting pin.
If you have confirmed it is the pump there is a company that repairs the electrical part of the pump at http://www.ecutesting.com/bosch_vp44_diesel_pump_repairs.html I have used these personally and their service is very good, they will repair the pump for a much cheaper cost than a new pump.
The main thing is to confirm that it is a pump fault ideally by having a diagnostic check carried out, if you want to do this yourself a cheap scan tool is http://www.ebay.co.uk/itm/Sealey-Eobd-Code-Reader-Diagnostic-Tools-Service-Scan-Tools-Work-Tools-/111036126964?pt=UK_Hand_Tools_Equipment&hash=item19da44d6f4 but you can probably have a diagnostic done for around this price anyway.
Let me know if I can assist further or if you have more questions regarding this and I'll reply as soon as I'm able to.