I think you'll be OK at Saltaire - it's quite a big venue.
Otley is smaller and you would come second to all the people with day and weekend tickets who get priority...
I think Nigel is calling it a "Folk Revue". It has a narrative thread running through it, with full length and partial songs, and prose and poetic elements. I don't think it fulfills the (apparently) formal criteria of a true ballad opera, but probably is a folk opera.