You are not alone Drisser 
I had negotiated my Mk7 GTI order on Monday, reasonable discount and trade in for my current 3 series. Expected delivery January 2014.
I then had a chance to try a m135i on Tuesday, sweet mother that thing shifts. After a few hours with my local dealer, whom my current car was bought from and after discussing my potential mk7 gti purchase they put an offer together. Some easy haggling later a very well specified m135i list price £35240 was purchased for just over £29k. I also secured an extra £1500 for my trade in and my delivery is expected 1st week in october.
I'm just down the road from you in Stirling. Really really loved the Mk7 GTI but the sheer performance in the BMW just sold it for me.
Yep, identical situation really, I was sold on the Golf, but BMW put together a compelling deal, and when I sat down and actually worked it out, its cheaper than if I specced the Golf PP to same level (I have leather and NAV on the 135 and discounted it will cost me around £800 more than the Golf I specced which didnt have either)
The real clincher at the moment is the lead time - people will wait 6-9 months for an Aston or Porsche 911 maybe, but not a mainstream hatch. Plus I have an MOT due end of the year so you dont want to shell out on a service, tyres, etc just because a manufacturer cant give you ANY info.
Sad situation really - some demand is good, too much demand and poor service is a no no.
Still, i will enjoy the BMW also I am sure. What spec did you go for ?