Hi Ted
My local "exchange" (actually a brick hut next to a pumping station) is Brandon Creek ( 01353 676 *** ) which, as it happens, is just inside Norfolk by a few yards.
I'm certainly too far, and on the wrong cable (4.9km of copper cable, much of which is suspended in the air); but the "exchange" itself has no ADSL kit in it, according to BT, and in any case it only serves a few dozen addresses. I've never found it on the trigger lists, but maybe my search was inefficient!
Here's the direct link for the exchange trigger levels.
http://www.adslguide.org.uk/availability/btprereg.asp?order=trig
Brandon Creek has a grand total of 9 pre-registrations! But no trigger level set so, as you say, could well be a candidate for wireless sometime in the future.
Good luck! Syd