The public transport issue is pretty serious if you're coming from north of Sheffield. I was keen to go to the Malcolm Douglas memorial ceilidh band event last year, and gave up when I realized how long it was going to take (the railway line was closed for repairs that weekend and I'd have had to do the whole trip on buses). From anywhere in Scotland, London is far more accessible. For that matter, I can get to Istanbul quicker than Sheffield.

Given that this is going to be an overnighter for most people outside London, it certainly makes sense to organize some sort of social/musical event to tie in with it.