Riding seat (6)
I believe the answer is:
saddle
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">riding seat</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for saddle that I've seen before include "Cycle seat" , "Leathery" , "Rider's seat" , "Equestrian equipment" , "Seat on horse, bicycle etc" .)