Left-winger's jumping well over tall ref (6,9)
I believe the answer is:
fellow traveller
'left-winger's' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'jumping well over tall ref' is the wordplay.
'jumping' indicates anagramming the letters.
'well'+'over'+'tall'+'ref'='wellovertallref'
'wellovertallref' is an anagram of 'FELLOW-TRAVELLER'.
Can you help me to learn more?
(Other definitions for fellow traveller that I've seen before include "like gypsy" , "one with leftist leanings" , "Communist sympathiser" , "political ally" , "left supporter" .)