Well i shall update my situation i guess. I had to admit defeat on this as i was moving house, i left the alfa in York with my dad who said he would have a look see if he could find anything i wasn't seeing.
Well he gave in pretty quickly and limped it a garage (supposed alfa specialist), they changed the EGR & MAF (and i think map) for brand new genuine bosch parts and the car did then start running albeit not perfectly. Dad took it back and they got really defensive and refused to accept there was anything else wrong with it but said their computer indicates the DPF is quite blocked and that if we give them another small fortune they would change it.
At this point i told my dad to just take the car and leave it at my mates for me to go collect when i had a chance, i asked my mate if he wouldn't mind dropping the dpf off and seeing what he thought and bash the innards out and in the meantime got a dongle off fixitsan to cancel dpf warnings and regens.
Now turns out when i went to get the car with my dongle in hand and an egr blank that my mate hadn't had time to look at the car and so i decided to do a bit of logging now the car actually runs and drives. And low and behold the dpf pressure differential looks fine to me, there is infact no difference in pressure at all at idle and only a small difference when driving so pretty sure the dpf is not blocked. The car btw has done alot of blasting up and down motorways and has been doing regular regens so i'm not hugely surprised by this, it rarely dives around town and sits in traffic.
And as before, while idling and even driving everything appears to OK apart from this parameter called 'throttle angle' - that is still stuck fast exactly same number as before (4.997).
Now the car in general runs ok now but its not happy starting at all - it almost fires a few times before it actually starts. Once running it idles fine and it goes flat out fine although feels a bit down on power compared to before all this began, it can blast down a motorway in 6th no problem and pull still in 6th.
However, at slow speeds under partial throttle its stuttering, almost like a petrol car misfiring but without the bang - now being they don't have spark plugs my initial thought was this has got to be an injector but again driving under all conditions the injector correction values all look close to zero and all not far from each other and no change when the stutter occurs. Which basically leaves me with this 'throttle angle' value thats staying constant. There must be someone on here that knows exactly what flap/actuator/whatever this is referring to, and if not can someone pretty please with beer on top try connecting MES to their car and checking this value to see if it changes like a think it should.
Do you think i'm at opening up the inlet mani to clean it and that might be the issue, particularly if my old EGR was stuck open a bit i'm thinking it might just be super coked up in the inlet (already checked i have the half plastic half metal one that comes apart) - And if i do do that, i'm thinking this 'throttle angle' must have an actuator - have read something about swirl flaps, could it be this? I have no knowledge of what they do and what they are for or where they are on the jtdm engine.
Any help with this would be greatly appreciated, kinda getting to the end of my tether with it.