Interesting thing about this huge, and in some people's eyes, ugly structure....and according to at least one in the know, true.....
NATS wanted the radar for tests, trials and development but expected to have to site it some way from the Engineering Centre because the planning rules looked like the Local Authority wouldn't or couldn't approve something this big, even in the light industrial area in which it's located. When they put the planning application for the mounting in it was described as a 23cm radar support structure or something similar. The council did the math quickly and said if it's only 2ft high it can't be a problem and approved it.
I guess when they asked to put the turning gear and antenna on top they either didn't want to admit the error or though 'What the heck, it can't make it any uglier!'