I always know these old houses in Swindon town centre have their problems, we had to fix a lot of the brickwork in the far corner (which allowed us to install a lintel for the niche). Two walls had to be dabbed as they were so bad, and the window reveals squared up. The sash window had a window sill also, this was removed, and an architrave frame was installed for a more in keeping look. But this is what we love doing as now look at the end result.