Well thanks for the nice thoughts folks, and I'm really looking forward to this one.
I would prefer to borrow a guitar than to lug one around. However, I am going to be around for a couple of weeks after the festival, visiting with a few folks. This means I really need a guitar for a fortnight.
What might work would be for me to bring my D28, and borrow a 12 string for the festival weekend. I play a Tanglewood, and I have also played and liked a Taylor 12.{Kendall has a lovely 12 string ;)]
It's a big ask, so don't feel obliged to go overboard on this one.
Regards
John