what about native Rowan? good flowers for bees butterflies moths etc/ berries for the birds and good leaf colour. Light and airy branches too.

I can think of nothing better than the pyrus calleryana aka ornamental pear tree. It flowers beautifully in the spring, leafs out providing good cover and shade, turns a nice colour of red in the fall and as an added bonus drops all of its leaves at one time. The roots go deep so it is not a side walk lifter or a asphalt cracker. You may further inquire on the web to inform yourself of its further attributes such as height, width, disease resistance etc.

The only "problem" with rowan would be the tasty berries and bird poo on the cars, it being a car park there's bound to be complaints from some

Silver birches are really beautiful and I love them but they drop something all the time, it seems, and there is a lot of clearing up to do. Their seeds get stuck in all crevices of cars and hang around for ages. One on the verge near my house is definitely shallow rooted and has pushed up the pavement.
Loosestrife's ornamental pear sounds about right!

Yes trees can be messy at times and the ornamental pear does drop its white flower clusters in the spring and its scarlet red leaves in the fall but both happen within a period of one or two days so cleanup is quick. These trees are preferred for pedestrian city and town sidewalks and store parking lots in the USA where I reside.