Great Chesterford is in the county of Essex, but so close to Cambridge that it is a commuter village for Cambridge. It is a relatively small village but with a few high tech companies in new purpose-bulilt premises. I suspect that if the people you are hunting are as itinerant as most others, they may appear in either Essex or Cambridgeshire, so cross posting would not go amiss.
It is a village of (I'm guessing based on a comparison with other places) 2000 or so people and a railway station on the Cambridge to Liverpool St line into London, so popular with commuters to both destinations.
