With all the information you have shouldn't be too hard....not.
I've used a number of Part Number /NSN crossreferences and found zero. The contract number doesn't match anything. Now down to contacting the archive/history offices at a couple Air Force places.
It appears that it is most likely Thor. There were 6 or 8 squadrons based in the UK from 1958 to 1963 or so, so a certain amount of material left behind is reasonable. The history types seem more into squadron/unit histories and aircraft/missiles. I guess nobody looks at the tow tractors/test equipment/yellow gear/etc...just the sexy flyingstuff.