Just to throw a curve ball, A Toyota iQ2 or iQ3.
Reasons:
It looks small but it's the same width as any decent cars, thus seating 2 in the front is extremely comfortable. The doors are really wide so 'access' should be come an issue or required, isn't a problem, seats are fairly high too.
Petrol, decent MPG and the back seats can be thrown down for ample of boot space for golf clubs. With the seats up though, you can seat 1.5 people comfortably but only a brief case size boot. I know it doesn't sound 'great' with this aspect but I'm suggesting this because on 2 of my outing since owning this cars, retired folks been wooing and ahhing at my car.
Seriously, it seems to draw them towards me like I'm a post office opening at 9am.
There's also parking sensor available if really desired - or if you're lucky to find one fitted already. No road tax, driving into London CC is free (both only applies to post 2010 iQs AFAIK). Did I mention old people seems to gravitates to them?
For £12K, you can have it near Brand New with everything thrown in or a half decent iQ2 at 2 to 3 years old around £8K mint. The iQ3 is a little faster but road tax band A (£30) and London CC charge, if it's something worth noting. Oh and parking this 'short' car is a doddle, never had an issue finding parking in half spots when in town.
Just a thought.