Just thought I'd update you on how it went.First observation: Saturday morning workshops when there are no concerts on elsewhere are better attended than Sunday afternoon ones when there are loads of concerts, ceilidhs, street events and sessions on!
Second: lots of people of varying abilities can be difficult to give very much individual attention to.
Third: a total of two hours is too short a time to teach very much - but loads of time to show some tricks, talk about basics and an approach, and play a few tunes together.
I think my workshopees all gained something from their time. I started very basic and went quite fast through to slides, hammer-ons and pull-offs; and we talked about performance and building confidence gradually.
What would I do differently next time? Maybe some more hand-outs on picking patterns and chord theory. Otherwise the developing a two chord song seemed to work quite well: it allowed a breadth of abilities to be covered.
Thanks again to those who helped me prepare for this.
Will I do it again? I dunno. Probably.