I'm hoping I can get some info etc on replacing a window/sliding door with a brick veneer wall. To minimise the time with the wall being open to the elements I'm looking to pre-build the frame, then remove the window/door install the frame and then brick up the wall then plaster. The window/door is around 2300 x 2100. The exterior wall will be rendered so the bricks themselves won't need to be an exact match to the originals. I've built a frame and plastered before but have never laid bricks. Is how I'm planning to attack the project OK? Is it safe to pre build the frame - or should I build it in once the window is removed?