Foxes are fine, but fox charities/rescue/wildlife experts do not recommend feeding foxes, they do absolutely fine on their own and they are not endangered. Main reason is they become too reliant, what happens when your neighbour goes on holiday, moves or dies?!
She's trying to be kind but she isn't. Foxes also as the OP knows, don't understand that one garden is fine, next doors isn't, not the foxes fault but will seriously piss off neighbours. They dig lawns looking for grubs, chew plants, poop their sticky black poop as scent markers, wee everywhere. No they better where they were for relations.
As you can tell, my neighbour 4 doors down feeds them. My once healthy (endangered) hedgehog population has all gone, never forget the sound of a hedgehog screaming at 3am, while being attacked. Seen hedgehog bodies eaten from the belly. My neighbour is a tosser. Just let nature be.
OP, only way to stop them, 95% of the time is to buy the expensive cat proof netting for your fences.