[Paulj]

Nematodes do work if used properly and it doesn't rain too much when you water them in.  I used them last year in our garden herb patch with good results.

They can be expensive though to get decent coverage, and for some reasonim not confident about them on the allotment. Ive taken the plunge and decided to buy a 20 litre bag of slug gone wool pellets. They sound more permanent and less susceptible to other problems like the rain and should be stupid doggy friendly.