This is an interesting one.
After a little search on Flickr I found out it was new as a 2-door bendy before being turned to a 3-door back in 2008. It also has a standard National Express interior.
So I guess it was originally destined to the Travel Coventry fleet but for some reason end up speding its days on the tarmac in Manchester airport. http://www.flickr.com/photos/coptercrazy/7086742215/
Perhaps the farebox behind the windscreen tells me that it can't be a London bendy.