Leopard Slug Hideaway

Over the last 2 days I've discovered an unusual hideaway for those pesky slugs.
On two of my water butts I have a section that breaks into the gutter down pipe, these sections have octagonal lids.
Since we've had the much awaited rain I've checked my water butts and have discovered 10 large Leopard Slugs hidden away under the lids. As the lids are tightly on I presume they must have washed off the roof?
Don't know if they would breed in this environment and the eggs etc be spread via watering from the butts.
So it maybe worthwhile checking your butts

I see snowdrop has checked her butt already   will do, thanks lincsman (I lived in Lincon once)

My butt is slug-free I am pleased to say,  my colony of leopard slugs seem to live life upside down on the underside of my compost bin lid.