Never heard of nematodes but will defiantly look into them for next season.
I read about egg shells, but I would need a heck of a lot to scatter around my pots etc so they are out the question at the moment.
I couldn't wait for the slug pellets I bought off eBay to arrive so i went down b&q and got their own branded pellets which are wildlife friendly, I've scattered them on the ground all around my pots & containers and a light covering over my large raised bed and touch wood, so far I have only had the odd slug and snail so far, so hopefully that will be the end of the army of slugs and snails that was obliterating everything in their path!
Next season I will be on top of pest control, and hopefully try out some of the more eco friendly options.
Cheers all.