As pointed out in the link via TwickFolk above:

Serena Cross states
"I recently produced BBC Four's The Christmas Session, for which Thea and her husband-producer-guitarist-sometime co-writer Nigel Stonier turned up mid-tour to Shoreditch Town Hall, gamely donned Dickensian top hats and tails and immediately launched into a version of her Christmas single, helped out by folk musicians they'd never met before that afternoon."

http://www.bbc.co.uk/blogs/bbcmusic/2009/12/christmas_records_day_17_thea.html#comments

A show and 13 out takes where there is no evidence of petulance or hissyfits by any performer only their professionalism to overcome difficulties and make it work certainly gets the thumbs up from me. Well done everyone and hopefully the production team will have learnt from the experience too.