I too have a 2008 GTI. Love the car to bits that neither mk 6 nor mk 7 interests me. For me... I would have kept my GTI and ask my daughter to buy her own Golf. LOL!
One friend asked me if I would buy a Merc A-class AMG.. I said no.. I already got a Golf ;oP
The clue is a big one but you say it beat the Golf in every area and that's not true of the A45, not even close in the real world/public roads actually.
Another hint?
If it were me, I'd go something from BMW simply because it's going to be a much different driving experience. In fact, I'm this close to ordering a 135.