Indeed, I agree with your last sentence.............
With regards to Aviance handling the LHR diversions, I thought they only looked after BA, if I remember Servisair have handled United, Virgin Atlantic & Delta in the past years.
Aviance only handle BA due to the British Airways Express / Manx Airlines franchise etc all those years back.
Bit odd why Eastern opted for EXT and not CWL - they dont even operate on a regular basis at EXT yet they have daily flights through CWL.....wierd.