I flew LHR NCL LHR on 20/21 October and the weather was poor. Was it storm Ophelia or something. Both flights had slot delays as Heathrow was on reduced arrival flows. One delay was small and one long and virtually everybody Heathrow bound missed their onward flights despite being told all flights were operating with delays. LH only had 10/15 min delays. I’m pretty sure if my memory serves me right that the weather wasn’t that great on 19 Oct so maybe that was the reason BA refused EU261