Another good, fun puzzle.
That said, while the answer to 16d is 'seems' clear enough, the parsing has me baffled, especially the reference to 'liberal' - 'L' doesn't appear anywhere in my answer so 'dropping it back two places' is out of the question. It would sort of make sense if the L were to be swapped with another letter but that's about as far as I get!
16d Ousting when liberal drops back two places in poll (8)