Spaces are rediculously small. Even with a small car it's often not possible to walk between cars without having to turn side on. Never mind opening a door and actually getting in.
That's because you're a fat git

On a more serious point though, you are bang on the money with regard the size of the actual available space.
I must admit, the traffic density and price of fuel are making me start to think about something "modestly-powered, but steerable on the throttle". 
A RWD Avion would fit the bill perfectly. 
Believe it or not, our 318 does quite well in that department once you switch the ESP off.
Granted you really have to plant the throttle (and make sure you do it at the right time), but it is doable thanks to having 140BHP and 130 lb/ft of torque available (which is quite respectable for a 1.9 litre IMO).
Fuel economy wise, I can do Leics & back (250 mile round trip) on £35 at todays fuel prices.
Haven't bothered to work out exactly what town driving gives, but I'm getting at least 30mpg without a problem.