The rest of QUICK ON THE DRAW is an anagram of TOWN HEARD. But this is the first time I've come across VAGRANT being used as an anagram indicator.
Please can anyone explain 41a? The clue reads:
One's perhaps served left-leaning 39's popular goal (6,4). (I think the 39 refers to the answer to 39a, which is LIBERAL PARTY.)
The answer looks like TENNIS BALL (= one's perhaps served), but I don't see how the rest of the parsing works. All help gratefully received!