MM4,
I suspect there is no shortage of space at Yeovilton. The hangars on the south side of the airfield could take most of the Merlin Force with ease (and with plenty of headroom). It may just be that the proposed lay down of space on the north side of the airfield makes it appear tight. Anyway for the next few years the aircraft will be going through the Mk4 upgrade so space will hardly be an issue.