Good info, ta.
I'm a little taller than you so bit of a worry there - can you fit a child seat in the back? If I can't safely squeeze a 5 year old (booster) and a 2 year old (child seat) in the back for the occasional short journey then I'm a bit stuffed....
I'm 6 foot mate and found the GTV slightly cramped for the first few days but after that you feel alot better and more like you are in the cockpit of a race car,
Take one for a test drive to see if you fit in it alright, you should do, they're not that bad.
The back should be fine for kids mate, but once they're over 8 I'd wager you'd have to taken another car if you the missus and the kids were off out.
The GTV Twinny was brilliant and went like stink, the V6 is even quicker and will blow your mind. The good thing now is mate you only have to worry about specialist services instead of bothering with a dealer.
A good specialist will charge around £100 or so per service but you'll need to change your cambelt every 72K / 5 years, this should cost around £400 or so, because if I remember correctly didn't the GTV come with the metal impellor water pump meaning they don't have to be changed as well as the cambelt??? I think that's correct.
Boot space is awful. My Fiat Coupe 20VT had more room in the front, in the back and in the boot, but it wasn't a GTV... BUT, I'm not a badge snob or anything so didn't mind the Coupe at all, cracking car,
Good luck though buddy.