Social / recreational definitely, I'd only be turning up for the beer ..
, but maybe more of a tek expo than seaside lightshow ??
Just as a matter of interest, there is a service called the "Mega-Bus" that runs from Cardiff to London, and if you book 2 weeks or so in advance a return ticket is only £8 .. and the late return leaves London at 11pm, so you can get a pretty long day out of it ...
Looking at the website this is a national service, so a return from Manchester just for example is only £9 return.
- does sort of make London the fairly cost-effective from a travelling point of view, albeit a venue might be more interesting to come by.
(that said, West-end pubs tend to be fairly empty mid-week evenings ..)