One way to deter mammals is to hang an old pair of tights up, and regularly put the hair from your/the misses' hairbrush in them. The smell of human will be strong enough to make the fox etc think that a human is hiding unseen. Hair has to be changed regularly.
May attract human knicker sniffing perverts though.
Rattling a few rounds off a metal sheet will frighten things away too. Chap I knew kept a fox away by blatting a sheet of corrugated iron with an airgun. Another friend did similar with sheets of steel plate placed about his farm in Nigeria. The Fulani herders would occasionally try to graze their stock upon his crops, and he would shoot the plates with a .416 Rigby or if at distance, a scoped LM .338. There's never a need for cruelty. Being 50 yards away from a plate hit with 6375J of energy probably caused a few brown trousers though...