Thanks for the replies so far.

I get the car back on Monday and will try and hang on to it for some more extensive testing. I will carry out some more diagnostics including a full smoke test to check for leaks and a look at the electrical switching on the injectors, as well as MAF performance now I have some idea ,thanks to George, of the frequency response, as well as a ckeck on EGR behaviour.

I do have a DPF differential pressure reading but thought it was something like 1 Kpa so need to recheck the value as when I looked at it I assumed it was OK i.e. it was nearly zero. Learned a lot about the DPF sensor on a 2.0 HDI peugeot the other day so have a good idea what values to expect but they were in mBar and yes at idle we should expect 0 pressure differential if the filter is unblocked and the sensor OK.

If nothing comes up I may try and force a regen although the Launch does not have this option or get a Tech2 from somewhere, or take it for a drive if the smoke is manageable.

Let you know how I get on .

George