Hi Ladbrokes, sorry to hear about your poor lettuces etc, I can well understand how you must feel.
I do find mine seem to be well protected by using Slug Gone, which I surround every lettuce, row of peas etc with, and so far nothing has been attacked at all. Slug Gone is made from sheeps wool and dried into pellets, so is very easy to use, and forms a mat when it’s been rained on or watered, which the slugs won’t cross as apparently it irritates them to move over it, so they don’t!
I’d highly recommend it anyway, if you’re interested. I bought mine online quite easily – I just googled it.