AIUI all Sky Digital boxes have had hardware support for DiSEqC, from Day 1 of their digital platform. Until relatively recently though Sky haven't made any use of it, so it's remained an invisible feature, not accessible through the standard UI.
DiSEqC is being used now though in Sky's implementation of the SCR (single cable routing, aka 'Unicable' or 'One-Liner') system where one RF (1st IF, really) cable can be passively split to feed up to 5 (? exact number) tuners. This works by putting intelligence in the LNB or multiswitch in the form of IF-IF frequency conversion, so the LNB/switch can 'serve' a required transponder/multiplex on an IF channel dedicated to a particular tuner.
Full protocol details are in EN 50494.