Foxes & cabbages?!

It sounds like a Brothers Grimm fairytale but I'm having massive problems with urban foxes in my vegetable garden. And - with unerring regularity - it's the cabbages they go after!

I've got everything in raised beds, covered with green hoops and veggiemesh which has done a fantastic job of keeping out cabbage butterflies, carrot and beet fly - even slugs and snails struggle to get through. 

First year I've gone to that effort but now foxes seem to be the one pest I hadn't factored in. From what I can tell, they don't seem to be doing much more than jumping (!) on the tunnels and rolling around. It's happened a few times already and I've been able to rescue the cabbages by pruning broken leaves but last night the cabbages were ravaged again. One of the hoops is bent and some of the clips are chewed.. Yuck  

Any tips though? I've seen everything suggested from air pistols to tiger urine - or even human urine... I can't stop them getting into the garden as they can get over the fences. I could try chicken wire I guess.