Zooker and others, thanks for the Mediator info. I just remember the then ATSM at EGNM a few years ago discussing the cost of telephone links with the Tels chief. He was saying something about "having the Mediator line to fall back on" if they couldn't allow a direct link.
As for the Decca 424, which is what this thread started with, I can't think of anything to else to say about it. It's certainly stirred up some strong feelings and reactgions in the ATC community. Thankyou everybody