Join Date: May 2012
Location: Munich, Algarve, Sussex or S.F Bay Area
Programs: Mucci, BA Gold, A3*Gold, AA Plat, HH Gold, IHG Plat Amb, Marriott Plat
Posts: 4,193
Important advice here is to make a screenshot of other airline sites with seats in the required cabin for sale as well as explicitly asking BA to note in the PNR that it had been requested. Come CEDR that could tip it your way.
It often feels like BA is first to cancel in bad weather but London is often a more important route for many carriers whereas BA may well favour higher revenue routes over OSL.