Smallish cheapish automatic with room for four adults?

[KnowlWay]

DC are tall. DH tall. I want a new car that has plenty of head room in the back and is fine on motorways and town driving. Under £20K. Doesn’t need a big boot or lots of snazzy stuff. Anyone got a Fiat 500L?

I'd go for a Honda Jazz. WhatCar gives it 5/5 stars for front and rear passenger space:
www.whatcar.com/honda/jazz/hatchback/review/n17343/space-practicality

I wouldn't buy new though, I'd buy nearly new, if you can find a nearly new automatic.

www.whatcar.com/news/car-of-the-year-awards-2021-best-small-car-for-practicality/n22459

Ford Focus. Dull as dish water but will never let you down.