Why was this constituency on its creation not called ‘Coulsdon and Purley’ and the 1974 Croydon South retain its name rather than be renamed Croydon Central?

By this logic -

Acton would have been re-named Ealing East (it did not even become Ealing Acton till 1983).
Battersea South would have been re-named Wandsworth Central.
Paddington would have been re-named Westminster North West and St Marylebone Westminster North East.
Greenwich would have been re-named Greenwich North West.
Dulwich would have been re-named Southwark South.

Coulsden East:
Con: 2446 / 2382 / 2264
Alliance: 2022 / 2021 / 1912
Lab: 345 / 338 / 334

Croham:
Con: 2315 / 2225 / 2189
Alliance: 2117 / 1928 / 1905
Lab: 401 / 399 / 372
Green: 255

Indeed – but change in the northern wards is happening quickly. I cannot see any other party taking this seat in the near future, but, in a 1997-style landslide, the Conservative majority may well be much lower than in 1997 – and some hypthetical seat uniting most of Croydon South and New Addington could even be winnable in a “normal” landslide year for Labour in a decade or so.

I may have read elsewhere – not on this site – that it is split between other wards and constituencies (part of the site in Carshalton and Wallington?) Is this correct?

Broadly speaking, the airport buildings were in modern Croydon, along the Purley Way, and the airfield lay in modern Sutton – the part of Beddington South ward to the east of Foresters Drive and to the south of Stafford Road. Most of the Sutton section was replaced by the Roundshaw estate; the airport is commemorated by the aeronautical names of the streets.

I presume, perhaps in error, that this term will be his last (he’ll be 70 in 2015).

Now I don’t know how long ago that was, but I’ve been following the personnel of the cabinet and shadow cabinet since 1997 and the Conservatives were in government from 1979.
I must have missed that one.