Caesar's farewell (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">caesar's farewell</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for vale that I've seen before include "'''Sweet ... of Avoca, how calm could I rest'' (Moore) (4)'" , "Valley" , "Glen; goodbye!" , "Trough between ridges" , "Maida -, N. London area; farewell (archaic)" .)