Copper strips around raised bed. Paint raised bed with bitumen paint (they won't cross it).
Short term solution for while you are away, use the pet-friendly slug pellets, sharp grit and gravel around baby plants, and get hold of some guttering - if you can't wait, go out and get some from somewhere like B&Q, cut it into a few 1ft long lengths. Put it in the areas where the slugs like to congregate, upside-down, with pellets underneath. The slugs will head for this around sunrise, as they need somewhere dark and damp to hide so they don't get baked to death in the sunshine. The pellets should do the rest.
You can use the same trick when you're at home, just omit the pellets. Go out just before you go to work, and turn the guttering over to give the birds some breakfast, or have a bucket of saltwater or a weeding knife ready to despatch them.
Given you have a dog, I would seriously consider using nemaslug, as slugs carry lungworm which can be fatal for a dog - make sure all of the dog's toys are inside at night, as even the slime trails they leave behind can have the eggs in. Ask your vet if lungworm has reached your area yet when you go in for their annual checkup/boosters.