More pictures.
http://216.239.39.104/search?q=cache:27qYhTzmFg4J:www.hows.org.uk/personal/hillfigs/whit/whit.htm+Whittlesford+aerial&hl=en&ie=UTF-8
Looks flat as a pancake round there. So viewable only from the air?
So the builders must have been......
tall.