I don't know much about the Bad Bay. Looking around, it looks like there are many different models with different components and even wheelsizes, which would explain the big differences in price there are.
As for an alternative, £550 will get you a penny change for a 2011 Trek 7.3 Disc from Evans
. I've got the 2010 version (it's called the Valencia, gets good review on Evans) and bought my wife the 2011 version earlier this year. Very reliable and nice allround bike. Might be worth a look if you next drop down to Evans.
Handles well on the road, as well as light offroad/towpath/disused railway etc.
Last edited by fairymuff; 08-25-11 at 03:43 PM.