Crowland radar tower.

Hi, I meant to post this months ago – so the thread is old, but anyway.
In the summer of 1969, I had a girlfriend in Spalding. One Saturday a.m., whilst hitch-hiking, I was dropped off on that corner. I was there for maybe half an hour, during which time an American airman in uniform, came out of that old single-storey brick building that was at the base of the tower to have a look at me. There was barbed wire around the fencing top. He actually gave me a light for a cigarette, and went back inside. The only other thing I remember, was a large blue board, with United States Air Force in an arc over the Great Seal of the U.S, and a numbered unit in the thousands. I wish I could remember more. As an ardent aviation enthusiast for 40 years, I have, so far, been able to find nothing – but would imagine a possible association with Chicksands or maybe Croughton.
There you are, take it or leave it. The board was similar to those which appeared outside all U.S. facilities up until the 1980’s ?
Thanks.
Jes.