Hi FloBear, if you make sure there is a wayin/out of your garden and leave food and water out regularly you will probably have the pleasure of seeing Blue Boy back in your garden again. Most hoggies prefer NOT to eat slugs/snails and prefer beatles etc instead. Slugs can cause lungworm (i found a hog in may garden during the day yesterday and a visit to the recue confirmed lungworm and she is now on a course of treatment)
Its surprising how small a gap they can squeeze through, i have several gaps in my fence-some quite large but i'm still amazed when i see one squeeze under the panels or between the slats.
There will be many Autumn juveniles looking to fatten up before they hibernate so this time is crucial for supplementary feeding. Any hog under 500g is unlikely to survive the winter and may need to be overwintered with a fosterer and then released again once the weather improves.