It poured all day today until there was a slight reprieve in the late afternoon and I went to check on one of the lettuce beds in the half shaded damper spot and true enough the slugs were having a huge gathering! There were easily 2-4 slugs on each lettuce!
Thinking about the Helix Tosta tip, on the other hand, I reckon we have too much lettuces now to worry too much about some losses.