The "hand me down" strategy is true of short haul, they took the last Dan Air ordered B737-400 new from Boeing in early 1994 and before that British airtours got factory fresh B737-200s, but everything else short haul LGW was ex LHR or regions.
Not true of long haul though as British airtours did get a brand new B747-200 and the latter BA B747-400s were delivered new to LGW (via Cambridge for fitting out) as well as the AML B777 subfleet. So new B78Xs wouldn't be unprecedented.