Pax then, Steve: I was also trying to be helpful, and of course I had had read the word JUNE! But not knowing when Shez's 4 months starts and ends, it still seemed worthwhile to highlight other festivals within that period. (And the first 2 I mentioned really do specialise almost exclusively in unaccompanied singing.)
Agree with Johnny J that Keith is a nice festival, and IS in June!

And Guest Tim, when is that Falmouth Festival?