Common TA of 6000' is in progress, area around BB is being processed at the moment, expect results in either spring or autumn next year apparently. It's very slow progress as, for example, the SIDs from BB go to FL60 so have to change, so affect the NX traffic, BE traffic etc all of which have to be procedurally seperated, plus notification of changes to everyone for bases that used to be FL's around 45, 55 etc..