Alright expansion tank replaced now, got a new OEM one from my local VW dealer for €37 as that was the closest one available to where I live.
OldNewSurprisingly one of the easiest and quickest repair jobs I've ever done on the car, took about 15 minutes. I even had a pick ready to remove stuck hoses but they only needed a few jabs before sliding right off.
Absolutely no reason to even consider a temporary fix if you're able to source the parts locally, it's such an easy job.
Thanks for the advice lads