Thanks Sophia, this could be an option if all else fails.
Strange observation this morning: (after dosing heavily with ferts (containing copper) last night.
I always see HEAPS of snails on the glass in the morning before the lights come on but this morning NONE on the glass.. They are still there on plants, rocks etc. but it's like something is different... I will poison them slowly but surely, HE HE HEEEE (evil laughter)