I like the charity sentiment but any deep meaning Stay Another Day was originally meant to have was lost as soon as East 17 put on giant anoraks and started fawning around like idiots in the video.
I have a feeling that there were 2 videos for Stay Another Day at the time, the first being far more serious, and it was not even considered a Christmas song anyway, although a hit at that time of year hitting the top for 5 weeks, so at some point the video got changed into this second furry anorak version that is now the one remembered and joked over last week. I actually recall them all doing it on TOTP and all 4 of them were barechested underneath these thick coats hanging open around the piano, quite an odd look!
To be honest I couldn't see anything coming of it even if the original group got in touch. For a start I'm not sure they all like each other much anymore, plus with Comic Relief coming up, as Jack Dee's guesting mentioned, no doubt there will be a terrible charitable hit mash up from that getting promoted.