Hi Rodjon,
I'm pleased to say that we have not experienced any further greenfinch deaths since - I think - last year sometime.
ACTION TAKEN: When the problem was at its height in this area, my wife had the stroke of genius to scatter our birdseed on the lawn, rather than attempt to disinfect the feeders/birdtables. This was intended to minimise the possibility of infection transmission at a few 'focused' common feeding points.
BTW, her idea had a beneficial spin-off: the lawn is scarified free of charge and moss disapears like magic
Hope this helps.
scar