During my 27 years as a licensed aircraft engineer on the Concorde fleet I can not recall any type of rota for flying the aircraft. Whilst in theory it would be nice to equal their flying hours it was not possible as A/C engine hours would often dictate. The engine was made up of different modules & when that module became time x then the engine was changed & went away for the module to be replaced/overhauled.
You would often face a situation where you tried to limit flying hours of an A/C so you could change an engine to coincide with a service check. Also bearing in mind the delivery dates of each A/C G-BOAC was the first due to it having the BOAC reg. followed by OAA,OAB,OAD,OAE . OAF, & OAG both arrived later.
OAC returned to Filton under warranty for a while & OAG was laid up for a long time before being recommissioned . Whilst we had 28 engines on the wing through out the fleet there were only about 8 spare engines. Don't know about Air France Engines. Like all engines they suffer from ingestion of FOD & oil leaks etc. so engines never really went to their full time x hours. As a flying spanner on several charters you always prayed for G-BOAD as it was always the most reliable of the fleet.
They all had their own characteristics. Most Captains had a favourite A/C