Lots of supportive remarks -- what a friendly welcome!
Completely agree with Ken about 3 x 1 hour but can't be done: education comes in 3-hour lumps, to allow the officers time to unlock and escort etc. Yes, I'll plan in some music theory and printing off stuff they can take back and read.
Jerry's / Ken's wooden fingerboard might work. I'll find out what classes they have in that department, and if the lads attend that or others then yes, maybe they could be supervised to practise a bit during the break -- good idea.
never tried kazoos but you've got me thinking, Russell, hooray.
it's going to be interesting when I feel settled enough to ask the chaps whether they'd be willing to learn some explicitly prison-based ditties. Stuff by Johnny Cash and other songwriters who know what it's like being inside has gone down well, e.g. Boy named Sue; haven't yet offered, or been asked for, more personal songs about grieving. Children's songs are popular in one prison where recordings can be made to send to families (Storybook Dads project), so your kids don't grow up not knowing what you sound like.
Thanks again.