This is another suggestion from Tony Harper which was circulated some time ago but is still a goodie. I used to play golf around the old ruins that exist today and I was very surprised to see what a wonderful building it was in its hey day. Did you know there was a manor on the site beforehand that dates back to the Norman invasion? The hall was then built in 1553 over the river by Sir Henry Jernegan but when was it converted into a Gothic style house? What brought about the demise of this lovely hall? To find out more, please select the following article and also take time to select the arrows on the picture gallery to see some excellent photos of the hall:
http://www.lostheritage.org.uk/houses/lh_norfolk_costesseyhall.html
Here is a supplementary article that you may find of interest:
https://www.costesseypark.com/history/