Driver's guide (6)
I believe the answer is:
satnav
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">driver's guide</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for satnav that I've seen before include "Guide for driver" , "Savant (anag)" , "Device for finding one's way" , "Driver's aid" , "Route guide" .)