erratic running

Hi. I put my P38 into the garage to get the starter motor changed after I'd had trouble gettit to start and the AA said it was the starter. Got it back and it starts first time, so, much joy. However, when I pull away the engine runs rough ,as if it was missing on a cylinder, its diesel. When I push the accelerator down for kickdown, the revs go up and it keeps trying to change up but fails. The garage have it back but can't seem to find the problem. The engine ran fine before it went in, only the starting problem. Any ideas???

Look for things that might have been disturbed, there is for example the absolute manifold pressure pipe from the underside of the inlet manifold to a little gizmo on the fuel filter, it's just where a ham fisted mech might be if he got at the starter from the top.