I'm in eastbourne too but don't have a fox problem, just the small, windy garden problem!
Is there any way you can fence the garden to keep them out? Do you know anyone with a holly bush? Some twigs of holly or something else prickly put on the ground they are digging should put them off.
I knew somone who put chicken wire on the ground and covered it with bark. It looked nice and her cat problem stopped because they couldn't dig.
I wish you luck. Are they using your garden as part of their route or is someone nearby feeding them?
We have some good garden centres here that can advise you on coastal plants and you can use wind tolerant plants to protect those a bit more sensitive. Hebes are good for that and come in different sizes and colours. I have several hardy fuchsias which cope very well, also a hardy gypsophilla in a very exposed spot which is shooting again now. It gets so big in the summer I keep hoping people would help themselves to a few sprigs as they walk past!
ESK have a garden club and give very good advice with 10% off on club nights.

remember the fox goes out on patrol every night to places where he can find food ( people put out ) so you are on his route ... dont waste your money on repellent as you would have to use it all the time .. one way is to remove him from your area ! but there is a possibility that another will move in... good luck.