Being a "dogsbody" in this case meant wearing a scarf for an hour before the meeting to let it absorb my scent and then walking a few hundred metres on a zigzag course around the end of the playing fields and into the industrial estate where I then hid in a corner. After a while spent reading Twitter on my phone, I was "rescued"!
I had been told not to greet the dog until he has indicated to his handler that he had found the right person, and then he got his reward. Some treats and a play with his toy.
We then returned to the car park and I chatted with my friend's husband (who is actually doing the dog handling) while my friend accompanied another friend as she laid a new trail. As the dog is still being trained, it's important that the handler's assistant knows where the "victim" actually went so they know whether the dog is getting it right or not.
It was fascinating watching the dog working. The scent drifts and, at a point where the "victim" and the assistant had paused for a while as they discussed where to go next, it had formed what they call a scent pool and the dog appeared to think that the trail led up the wall by the church! But after casting around for a bit, he picked up the trail again and soon found the "victim" hiding behind some shrubs in pots.
Apparently some people volunteer to be dogsbodies on the weekend training events. They come with a bivvy bag, sandwiches, flask and a good book to read and spend the day lying out on a mountain. It actually sounds quite enjoyable in a weird sort of way.