So I used Citadel Athonian Camoshade on the body and turret, and Citadel Agrax Earthshade on the wheels and tracks. Unfortunately the shade dried with a mixed gloss and matt finish, so I used some Humbrol acrylic matt varnish (49) to get a common matt finish.
To recap, the tank was undercoated with Citadel Chaos Black followed by Humbrol Dark Green spray. The track and wheel treads were painted with a mix of Vallejo Black Grey and Hull Red. A mix containing more Hull Red was used on the ice cleats and the spare track links.
A similar mix was used on the exhaust pipes.