Rhys.
For the last two years I have been spraying veg., and plants that are high risk of slug/snail damage, with HELIX TOSTA. I have had amazing results, no damage to plants and no poisoned slugs for birds to eat. The slugs just seem repelled from eating. Probably something to do with HELIX TOSTA being made from toasted ground up snail shells!
You can buy the pills from a homeopathic supplier. I bought a new sprayer just for this job, as I did not want a trace any previous contents. Dissolve one pill per 200ml of water, spray on plants and soil, the effect will last for three to four months!
I hope this may be of interest to you and any other gardeners.
Anne Wood