Not a problem at all in fact the opposite a delight - we love seeing them. They visit our windowsill every evening and early morning to eat the peanuts we put out for them and then disappear back into the woods.Lidl in Glasgow still anti Marten spray. Apparently to use on cables to discourage nibbling. I had no idea martens were a problem, thought they were too rare and secretive in habits to come too near human habitation.
Are they really a problem anywhere? Guess this photo they could be.