5050mm looks a very good sized door, i read some where on the net that a standard double 14ft or 4267mm door isnt wide enough to take 2 standard cars side by side these days. Another 750mm doesnt sound a lot in the scale of things but i bet it makes a massive difference. Ive just ordered my new door at 14ft 6" or 4420mm hoping its ample enough.

Whats the depth of your garage? Did putting the door on the inside of brickwork make much difference ?