So Thomann sent me replacment volume knob and PCBs for free! See photo. Apparently covered under warranty.
I just need to pluck up the courage to lift the scratch plate and fit the new PCBs in place - hopefully not too difficult a job.
Thanks everyone (especially Thomann) who replied to my plea for help.
Cheers
Gary
I was wondering about changing the black plastic knobs for metal ones. Any advice on this and where I might get them to fit a Sire P7?