I surprised myself with how far I've managed to get with this. Full grid except for five. I assume they're all anagrams (rather than top or tails) because I need to make up the 12.
20 a Truly archaic goddess protects Troy (6) SET?E?
18 a Lift up daughter clutching woman's prize (6)
D?A?ER
2d Mostly dim types initially speak nonesense (5)
TA?LE
6d Old Indian copper pot originally one fabricated (4) OBE?
7d Triumphed pver the first of seven teams (5)
SIRE?
Almost there, but can't quite work these out - gentlest of hints appreciated