Flying Services stayed there after the fabrication business closed in 1948, moving to W Malling (c.1960) and lingering there till (c.1971). It did odd mods for MoS: the last was Varsity WL681 with odd excrescences, operated in support of Hunting Engineering’s work on UK’s nuke programme. I saw it at (grass, soggy) Rochester, 28/5/58, plus Canberra B.2 WD929, Sturgeon I TS476, Sturgeon T.T.2 (No.2 P) VR371 and THUM Mosquito T.T.35. In the 1950s, SB&H overhauled RAF/NATO Sabres, and long ran RNARY/Sydenham: all this support activity provided continuity when various licence production programmes (Swift, Comet 2, modest Britannia) floundered. I think (under another name) they were still operating RAE W Freugh up to its closure.