It should probably be safe, but I would put in earthworm castings to pump up the biological action in the soil, and also wash any produce thoroughly before eating--a good thing to do, anyway!

Not sure you can get earthworm casting in the UK... at least I've never seen them but you could add any organic matter such as compost. By the time your vegetables are grown any fouling by the cats will be long gone. Washing veg. is good practice though I only do so with root veg. and salad greens (when I remember!). Peas and broad beans come in handy containers so no need to wash.

What, no snow or snap peas, MG? : )

Nope... I like to pop my peas out of a pod :-) I also think we actually panic far to much dirt/wee on our veggie plants.

True. If you cook the veggies, no worries at all. If eaten raw, 99.9% of the germs are taken care of by our digestive enzymes and immune system. 99.9% of the surviving germs are harmless to humans.
The things to worry about are heavy metals--as from old, leaded paint, smelter slag used as path paving, and certain forms of sewage sludge based fertilizers. Detecting and dealing with them is harder!

Agreed Tugbrethil