I also couldn't get Petrograd, and didn't like the obscurity of tank
= Saladin. Having seen the answer here I've looked online and it seems this is incorrect as well as obscure, the Saladin had wheels and not tracks and so is not a tank, it was an armoured car.
Stuck on:
10d Coming across page, not fond of Shelley? The exact opposite (10).
a?t?p???s
20a Wickedness in dog suggested? (10)
?r?n???i?g. Could be 'wrongdoing' but I can't see the 'dog suggested'.
22d One is taken in by a most peculiar philosophy (6). ?a?i??
Maoism? Taoism?