So I take it that no-one has heard of Enhance Mode S (EHS) transponders then?

Take a look at the eurocontrol web site (or your own CAA web site and information circulars.)

For the record, it does not show SELECTED IAS, but actual IAS, however it does show SELECTED LEVEL (as an obvious aid to prevent level busts)

Yes, the dreaded mode S, big brother is only watching at this point. :}