Stuck on last few:
5a "Sort of acid to bring up, and fatty, mostly" (6)
Is it CITRIC i.e. CIT(E) and RIC(H) ?
8d "High-toxicity fat here. There's a councillor looking into it? (4,6) C?T? F?T?E?
20d "Movie sees him chasing Oscar" (6)
V?C?O? Looks like VICTOR but can't see the parsing
Any help appreciated