I had a new clutch cable recently - although I didn't get much of a problem with 1st (only had to really jam it in a couple of times over 3 or 4 days driving) I had the same problems with reverse. In the end, about 3-4 days after the problems began, the clutch cable went *snap*
thankfully it was fixed on the last day of my warranty!
I'm sure I read somewhere on the forum something along the lines of our GTi's not liking a lot of fast starts off the line, ie. lots of gas, on the bite, ragging it down the road on a regular basis, and that this causes more extreme wear on the clutch than normal (although I'm sure that any other car would have similar problems with repeated 'rally' starts...). You didn't take her down the strip a few times did ya? Might have contributed...
Could be only a simple allignment jobbie but

careful now...
Fingers crossed!