Well it didn't make any difference changing the date to ensure the show goes on - the downward trend of the past four months has continued, with only two fellow-singers at last night's session.
This makes no sense - and with no feedback from the previously enthusiastic absentees I'm forced to conclude that it might be the time to call it a day. It would be good to get some response before I have to make that decision, however, so now's the time to get in touch - please!