Ideally I’d say you want to stick a scope on it to look at the voltage and current draw with it running against a known good injector. 

Are these 2 wire injectors? 

Does it run with a constant miss or is it intermittent? 

11 hours ago, stef123 said:

Ideally I’d say you want to stick a scope on it to look at the voltage and current draw with it running against a known good injector. 

Are these 2 wire injectors? 

Does it run with a constant miss or is it intermittent? 

I don't have a scope unfortunately, would hope the Diesel specialist did though.

They are 2 wire injectors.

Last time I scanned it, it was a constant miss and the error code was currently present, returning immediately after clearing.  This time (since the garage had it back) it was an intermittent miss at dual carriageway speeds (I trust the owners word on that) and the code was there but not present at the time of scanning so potentially not cleared by the garage.   It wasn't missing at idle after I cleared the code, and the code didn't return at idle or a brief rev to 3k ish.  Didn't have the time to wait for the owner to take it for a fast run before rescanning unfortunately.