OK, enough with guess the story.
So , when we took out the toilet last November and changed the soil pipe it left a gaping hole in the wall. This was patched up on the inside but I figured that if get around to the outside when I get around to the outside. So this is me getting around to the outside. Why is the hole so big for a 4" pipe you may wonder. It's not that I went crazy with a power chisel - although it was fun to do. The old toilet was actually on an angle so it created an extra large hole when we straightened the pipe.
So in first with the expanding foam to insulate and fill the gaps. Just shake the can, insert the nozzle and fill the foam. Then you watch it expand, and expand, and expand, and EXPAND! As you can see, I completely underestimated the expansiveness of the foam. It exted up looking like i jammed a giant marshmallow on steroids into the hole.
Good thing it's easy to cut when it dries. I used an old serrated kitchen knife which worked a treat. Don't ever try and clean excess off before it sets as it is stickier than a giant melted marshmallow on steroids.
Once the foam was cut away, I used a bolster to cut bricks to size and fixed them using a lime mortar. As I've been reading, lime is important for flexing and water egress. Particularly important in older buildings that would have originally used lime. After it set, I used the same mortar for the rendering. Done in a couple of coats to get the right finish. This was finished off with a wet sponge and voila, no hole.
I'll finish off the paint when the weather gets a bit warmer.