For civilian DME? Are you sure? I used the kit in JP, Vampire, and Hunter, through the 60s. My recollection is that, with a few exceptions, the ground beacons were only on RAF bases (maybe RN? Not sure). Coverage in the UK was good, overseas pretty minimal. When ferrying Hunters between UK and the Gulf, we had beacons available at Luqa, El Adem, Akrotiri, and by prior request Teheran (Mehrabad), then Bahrain, Sharjah, and probably Masirah - memory is a bit hazy. The Hunter 9 had an ADF as well (which was not a whole heap of use), but navigating much of that route was mostly point and hope - and hope the cloud was sufficiently broken to be able to map read. Happy days!
If you do find evidence of civil use, I would be intrigued to learn the details.