I usually invite visitors to tell me why this area is known as the 'Norman' porch. It is hard to work out. The architectural style is clearly not Norman. There are no paintings of the Norman Kings - or even their coats of arms (the coats of arms of the saxon Kings are on the wall alongside the Royal Staircase). The busts are of Prime Ministers who were or became Peers.
The answer is that the original plan was to place busts of the Norman Kings in this area. It was never done - but the name remained.