Dmf problem ???

[Benscab]

2014 Astra 1.6 diesel

Around 2 weeks ago I went to overtake a wagon and as soon as I throttled it....... BOOM !  Management light came on and car went into limp mode.  
Limped home and plugged in my trusty £15 diagnostic machine and got P0299 turbo underboost. Cleared the fault and all seemed fine for a few days , then I noticed what seemed to be what I can only describe as a stuttering from the engine and the gears were getting difficult to select but not slipping out of gear , also when standing at lights in first gear with clutch depressed there is a rattling noise. This made me think Dual Mass Flywheel, but surely that wouldn’t cause the turbo underboost would it ?  Or vice versa ?
Anywho I have it booked in at a local garage to fit a new clutch and flywheel, but now I’m starting to doubt myself , I can’t really afford to be spending £100’s  on the dmf if it’s something else causing the problem.

Hoping someone has had similar problems or can shed any light on what the problem could be.

Thank you in advance for any and all assistance you may be able to offer.