I am beginning to smell a rodent here. I just looked at a couple of the flights mentioned and found:
G-EUUK 1st October Petition claims "fume event" on BA811. History says BA811 was due at 20:35, landed 20:41.
Petition says G-EUPL flew BA839 to Brussels 1st October. It actually flew BA812 to CPH and back as BA813 and again as BA816/7. It did fly to Brussels though on Oct 7th.
According to the petition, G-CIVF diverted to Chicago due to a "fume event" on 17th Sept. It actually diverted due to an electrical fire.
BA861 3rd October (G-EUUM) was due in LHR from Prague at 18:20. Landed at 18:19. For some unknown reason it was delayed departing for Marseille that evening as BA330
G-DBCD allegedly was affected twice on October 3rd, first on BA2622, LGW-NCE. Well, that flight arrived at Nice 3 minutes early, departed for its next "fume flight" BA2623, back to LGW. Departed 10 mins late and arrived at LGW 10 minutes late. No time there for a "fume event". It flew 4 more sectors that day (Turin and back, Glasgow and back). Busy day for a sick aeroplane!