Correcting an error in perspective

What to do to correct an error in perspective in a grisaille underpainting...

Yesterday, I posted in my blog that I had made an error in the perspective in the roof of a building in a grisaille underpainting that I have done. There are a number of things that I could now do to correct this error....

leave the perspective wonky and give it a "Picasso" like look (suggested by a reader - not bad)
trash the painting entirely
try to erase and redraw the persepctive correctly (which is what I have attempted to do...

Take a look at the progress made on this painting and note the correction in the building.