my next door neighbour is having one done, seems to be taking forever! theres allways different plumbers/electricians about, maybe they are having more work donw on the house, still got a garage door on it tho :S surely the brick wall and window would come first?
depends on the end result mate, leavin the door on till last aint a bad idea...
1) you can leave the knockthrough till last
2) you just roll up the door and you got complete access for materials
3) you can do 3 sides, the ceiling, even the floor, 1st fix/skimmed/2nd fix then just boot the hole out for the access into the room, dig a quick footing, get the inspector down, level/insulation check, dryish mix the concrete, build straight off it and have your window in for nightfall, day after dab em, skim em, window board..job done...
still if theyve been there forever it sounds like a complete self build...
its possible to do a basic 2 sockets, 1 rad, 1 knockthrough, full width window, 1 internal door in 7 days, 5 with a few good lads