Foxes and slugs

For the fox problem I would stick pea sticks in the ground at regular intervals (fairly close) to deter them. They can then be removed as you plant out.

Slugs- well there's a variety of methods, horticultural grit around plants, eggs shells, beer traps, comfrey leaves around the base of the plant, organic pellets (won't kill hedgehogs).. the list goes on..
Would be good to encourage hedgehogs, as they will eat snails and slugs, by being a bit untidy and having piles of leaves and logs around they may take up residence.