Had a similar problem here for the past 2 years.
Fox has decided take up residence at the back of our shed on a patch of waste ground between us and the boundary line to neighbours.Lasy summer we saw it most days sunbathing on the shed roof then later we saw it with severla young.They make a mess in the garden,smell like hell and scream at night.
Got really fed up with it so looked at all the options mentioned ,but problem is we have 2 cats that my wife wouldn,t dream of having poison left out .Eventually rang council to enquire if they could do simething as we considered them pests.We were told that they didn,t remove them and we would need to speak to a pest controller.
Found a guy who specialised in vermin control who said he would set traps in the garden at £75 then once the fox was caught he would "dispose " of it for another £75.I looked on fleabay and you can pick up the caged traps for £25/£35 then sell them on when used so that may be the way we go this year as really getting fed up with them in our garden.
Have tried the "pee" approach and it doesnt work,but I think once they have taken a den even if you get ride of one set they will return .