Our old knackered 146 only has one ADF, mind you it also has a Trimble 2102 thing that isn't connected to the Autopilot either. The ADF needle is on the HSI, just an outer ring, though the needles are splitable if two ADF inputs were available. The twin VOR fit is on the DBI, an RMI indication of the other side's HSI heading.
Pretty crap really, how they call it BRNAV compliant is beyond me, but it is vintage 1984 and number 15 off the line. Things you fly for a few quid, eh?
Our home field has an NDB/DME approach avialable, but we rarely use it as there is also an ILS at both ends and radar control as well.
More importantly, our control unit allows a second NDB frequency to be pre-dialed and flipped with the switch if a Go-around were required at other airports.
Did I mention it's only CAT 1 as well.....not even good enough to be a water bomber....