Shucks Dave, you say the nicest things.
I found this legal mumbo-jumbo about proximity endorsements
Air traffic controllers are required by the Civil Aviation Authority (the Regulator) to be certificated fit to carry out their duties. According to the standards operated publicly by the CAA, a person who has had a particular difficulty may have a restriction imposed upon him or her. This is called a proximity restriction. It applies:
“[w]here the medical certificate requires another suitably qualified controller to be in the close proximity and able to take over in an orderly fashion in the unlikely event that the individual should feel faint or unwell.”
““Close proximity” should mean “certainly in the same room, if not actually by the side of the individual concerned.” This means that another controller holding the appropriate ratings/certificate of competence, must be available in the same room for immediate take over and would rule out someone being down stairs in the tower if the aerodrome controller had a proximity endorsement, or, any monitoring by CCTV or similar means.”