Complex sentence: The ATC 2008 Bawtry Sqn, are currently having a new building being built, in the meantime they have moved to the old Cpls Mess at Finningley (Old RAF Finningley, now called Robin Hood Airport).
Split into simpler sentences: The ATC 2008 Bawtry Sqn, are currently having a new building. While this is being built, they have moved to the old Cpls Mess at Finningley (Old RAF Finningley, now called Robin Hood Airport).