. For example I fly out of Cambridge, and *all* approaches there require use of ADF (even the SRA and GPS approaches as part of the missed approach procedure)...
I don't know about UK but in the US we are allowed to substitute GPS for ADF for determining position fixes so even if approach plate says 'ADF required' you don't need one provided your GPS receiver is approach certified. You only need one if you are actually flying an NDB approach and then you must use ADF for flying the final approach course. With this in mind and because there are so few NDB approaches left, modern GA aircraft don't even bother to have one installed.