Thanks all. Unfortunately the downgrade happened. Mr NW was given a £75 voucher and signed whatever was put in front of him without reading it and told he can contact BA Exec Club for further compensation. Some lawyer he is!!!! We'll have to see how things pan out but if BA are willing to dupe a GGL customer out of EU261 comp then I pity the average traveller.
Taking the downgrade was the lesser of two evils as he'll be home before the later flight boards and spending a day in Dubai airport would be a killer. Waiting until tomorrow is not an option since I am heading off tomorrow (on the glittery caviar serving airline that should not be mentioned on the BA board) and someone needs to be home to take care of the kids.
I'll work through the comp calculation posted up thread and let you know how we get on.