I visited my sister who lives in Poole, near Bournemouth this weekend.
It appears that she and her boyfriend are removing their shoes at the door. That was good to see.
I do not know whether they have a strict rule (they hardly needed to ask me to take mine off). I find it hard to imagine Heather insisting on people taking their shoes off, but I expect most of her friends would take their shoes off without being asked. They all have their own houses and apartments and would understand Heather's need to keep her house clean.
Carpet certainly is an issue for her. She would like to replace her carpet and she feels beige would look best. That means a lot of worry about keeping it clean. I think Heather's house is likely to stay shoe-free most of the time.