The bark chippings are a good idea, unfortunately my garden is too small to give the dog a dedicated poop area. There's not really much point anyway, as whenever I go out to clean up poop, I end up cleaning up at least as much cat poo as there is dog poo. If anyone has any ideas for keeping the cats away, I'd be interested (have tried super-soaker filled with beer and that works for a while, if I'm quick enough and my aim is OK!). Welshonion, I think the discs you're talking about are distraction discs, for use when the dog is doing something it shouldn't. I have trained dogs to go in a specific place in the past, you need to be very patient, find out when the dog normally does it's business, then take it out ON A LEAD to where you want it to go. When it goes, tell the dog 'Wee-wees' or 'poo-poos', and give lots of encouragement & treats when they've finished. They then associate the word and action, and in time the lead can be discarded, and when the dog gets let out, you can say 'wee-wees' and the dog will go to the area and do it's business.
We used to have two (sadly one had to be PTS earlier this year) and they understand this AND bedtime wee-wees - they know they won't be let out until next morning, so when we let Max out at night, he knows what's happening.
He also knows the difference between 'collect the boy' (from nursery, 30mins) and 'going shopping' (a couple of hours). But then he's a GSD Collie cross, so probably cleverer than I am!!