GVA would probably hold it's own relatively well for the summer. I think the problem EI have at ORK is there is business for more than 4 aircraft at ORK, but maybe not quite 5. Depending how summer 2010 goes, a 5th A320 might be possible for 2011. BHX could definitely support additional flying, probably MAN too, although RE might be better placed to operate those flights.
Brian.