Last year I tried Nemotodes but because my garden is kind of connected to my neighbours it wasn't that successful.
What about this www.crocus.co.uk/product/_/organic-slug-and-snail-killer/classid.2000022754/?affiliate=googleproductfeed&gclid=COOSmvC2ydICFQ4R0wodxsALbg
I don't want to use anything that will harm other wildlife (birds, worms, insects). Just flipping snails.