I thought I saw a handwritten 'shoes off' sign in the porch of a house in Droitwich today.
Of course I could have been mistaken, maybe it said 'Coats Off'. I thought it would have been rude to walk up their drive to have a look.
If it was a 'shoes off' sign, it would be the first I have ever seen. Not a British thing at all.
However, I did visit a home once whose owners had put a new floor in their bathroom. They had not yet varnished the wood and so had a sign outside the bathroom asking visitors to remove their shoes before going in. Silly people; what about the carpet in the rest of the house?