LDV 400 van judders when ignition switches off?

Hi, I have a LDV 400 series 1995 (M reg) Luton Van with the Peugeot 2.5 TDi engine.
I have just had the rear crank seal, full gearbox and a full new clutch replaced at an enormous cost unfortunately, due to having dealer original parts.
My Van now judders for 1/2 second as it switches off, with the ignition key, as though the fuel is not cutting off. Before it was perfect before it went in for repairs.
Some people r saying timing issue, some the solenoid on pump, some the pump etc? All help would be greatfully appreciated.