We exhibited at the Biz Start Up show a couple of years ago, and thinking of doing it next year, so wondered down to Earls Court today for a bit of a recce and to get some ideas.
The shows definitely grown since we were last there, and seems to have incorporated the Great British Business Show. A very busy event, and certainly packed out. Visitor numbers seemed to have overwhelmed the organizers, with long queues outside the event, even though we had already pre-registered online! In the end, security just simply opened all the doors and waved us all in

Catering facilities were pretty poor for the volume of people as well, I remember the Birmingham NEC show a few years ago seemed a much better organised event.
Anyone taking their car down, set off early as the carparks will be full before dinnertime.
But a good show and certainly worth a visit. If you are looking to capture a UK small business or start up audience, then it could well be worth considering a stand for next year.
The Great British Business Show, 17/18 November 2011
Starting a Business | Visit the Business Startup Show in London