Butterfly protection working

My butterfly protection is working like a charm. I've spotted several butterflies fluttering all round it looking for a way in. They're so hell bent on finding a way in some will even tolerate me taking photos of them. I haven't seen any sign of butterfly eggs or caterpillars inside it yet though. It doesn't seem to matter that the butterflies can now land on the tops of the leaves through the netting, they only want to lay their eggs on the under sides of the leaves, so it's still effective.

A Cabbage White desperately trying to get to my cabbages

It's a different matter with slugs, mind. They'll happily crawl up on top of the netting (I've seen their slime trails over the high parts of the net, suspended above the plants, but I haven't caught any at it yet). I suspect they're chomping the leaves through the holes.