2001 Fabia .19 TDi stuttering around 2k rpm

I have a 2001 Fabia Estate - 1.9 TDi.

Its started running a bit rough... I first started noticing it in a quite narrow rev range around 1800-2000 usually at slow speeds - it just got a tiny bit juddery/stuttery. Since then it has got a bit worse and now sometimes happens quite badly on the motorway over a wider range (1800-2200 maybe) which is annoying when in traffic going around 60. It tends not to happen until the engine is warm, and then lately when its been getting bad on these motorway trips I found turning the engine off and on again often sorts it out for the rest of that trip. I think there is a loss of power but its not too bad - I can still get on fine in traffic.

I've searched here, but most of the descriptions I found seem to be related to throttle - this problem seems to be independent of the accelerator - even when coasting it is juttery in that ref range and putting my foot down etc. doesn't seem to make much difference.

MOT/service is due in about 2 weeks so I was hoping to leave it until then, but wanted to check it wasn't likely to be something bad - I will have to do around 4 x 40mile trips between now and then (but thats all). I was hoping I could get through just by pulling over and turning off/on again as necessary.

Since the car is more or less worthless now I guess I was going to try an independent garage rather than a Skoda dealer - but if this is likely to require a vagcom fault read out I guess I should find a VW specialist? Or are all independent garages likely to have the computer stuff these days? (There is both a regular independent and a VW/German car specialist in my neighbourhood, both with very good reviews)

Thanks for any advice