Thanks, all, that's the sort of info I'm after. It does vary from place to place. Now, if I choose to do an exercise at an a/d unknown to me, is there any way of telling (you mention DME zeroed to threshold, Spitoon) from published info, whether that a/d's ILS DME will fail (or be switched off) if the other elements fail.
In the absence of any such info, I will of course continue to BS as I always have...