Long experience of "big" feet
First I would strongly suggest you always size shoes by EURO sizes they are far more reliable.
I am a UK13, EURO 48. I use both road (Look) and offroad (SPD) shoes, plus I use a size 49 in the winter for extra space for thick socks.
I have found the following
Shimano - selective shoes in 48/49, do tend to be a bit on the small side.
Carnac - good fit good size toe box and very comfortable.
Northwave - Good generous fit
Sidi - like Shimano a little on small side, but do many shoes up to a 50
Adidas - Yes really not sure what they offer these days but I lived with a pair of their road shoes and did me very well.