The advice given above was good. My sister in law contacted Bath and they looked into it for her. Unfortunately they only keep records for 100 years from the birth of the person concerned which ruled out our case.
We were looking for information on my father in law who worked for the Air Ministry at Cardington until 1956. We are fairly sure that he was a driver who delivered the gas bottles for the barrage balloon training department.
The family lived at Shortstown. What did your relatives do?