I would venture to suggest that Wroughton was all part of the "out station" push by certain London based national museums in the 70's, Margaret Weston being a big driver for this in the Science Museum. Some had misgivings for the placement of Concorde 002 in the FAAM at Yeovilton for this very reason, seeing it as a possible trojan horse for Science Museum expansionism.
My experience at the time indicated to me that Museum politics and motivation often went a lot further than the popular perception of being for the safeguarding and presentation of artefacts.