I've seen a fair few in Norwich, and a couple driven by young families too.
Single people, particularly women, like the 500 because it is fashionable, small, easy to drive, economical and relatively cheap. Two colleagues have them in fact, for just these reasons - and they have been reliable too.
The 500L certainly appeals to a broader spectrum of people, particularly as it is wholly practical in so many ways, which the 500 isn't - no glove box, only two doors and relatively poor rear space.
And then there is the price. The 500L is expensive and it is older people who tend to have the disposable cash.
As a comparison, I have seen about four of the Vauxhall Adams in the same time as I have seen three times as many 500ls. Here's a small car targeted wholly at young people, with little in the way of practicality - the back seats make the 500 feel like a limousine and the seats are set too low to make ingress and egress easy - not much in the way of looks, and a painful need to be fashionable. It doesn't seem to be selling at all well. And the price