I bought this old postcard from eBay and photographed it in situ. I also had a postcard of the Priory but the photo needed to be taken from inside the school playground and it's been closed and fenced off.
It's quite tricky to match up well, but I didn't do bad with this one. I moved it back and forward to one side to get the scale right and then adjusted the camera back and forward to get the perspective right.