downtoearth Your description of clothes-buying with a teenager made me laugh.
My Dad always used to laugh about the time he came with my 9 year old daughter and I to Crawley to buy her a coat/mac. We traipsed round dozens of shops, tried on dozens of coats and then, thoroughly exhausted and disheartened, returned to the first shop and bought the first coat she'd tried on (which , if my recollection is correct, she was then reluctant to wear).
As to food and children, if we are going out locally we go to Toby Carvery where there is a good choice of vegetables (for us and them), freshly roasted meat and a pleasant atmosphere. They enjoy pointing out the food they want, and the amount they want.
If we are in Central London, we go to China Town.