I have experienced a number of SOP's, including BA's. I can honestly say that it makes no odds whatsoever. Some of the BA SOP's seem like a good idea, and others less so. There really is more than one way to skin a cat III landing.
Personally I find a monitored approach ideal for CAT II/III conditions, but less useful for CAT I and visual approaches. Just a personal opinion.
But generally speaking BA always do things differently, just look at the Trident, it was a good idea until the company got it's claws into the design! How much did it cost to have autopilot engagement paddles instead of the standard buttons on Boeing a/c?
When I discover the perfect way to operate a/c I will let everyone know.