I had the same problem but have managed to get it under control. I use beer traps but don't sink them in as the ground beatles also fall in and you want them to eat other insects. I also use upturned bowls ( the terracotta coloured plastic plant pot trays are the favourite or half orange or grapefruit skins. Check them in the morning and pick up all sheltering slugs using an old spoon and throw them in the bin, also check undeer the beer traps, Go out at night with a torch and check your beer traps as a lot of slugs will pinch a drink without going for a swim. Night is the time to catch most slugs. Keep the area tidy with little for them to hide under, keep adjoining paths clear so they don't have cover to wander into your veg. They aren't supposed to like crossing copper (must be shiny!) although I have seen this happen. They also dislike crushed egg and sea shells. Sounds a lot but I only spend 5 minutes in the morning and again at night and it's made a massive difference, Best of luck