Don't think its Measure 22. The RN didn't use the American system of camouflage colours. Also Measure 22 would follow a horizontal line around the hull. The dark colour is clearly dipping towards the bow in the second photograph. It's more likely an Admiralty Standard scheme, my guess 507a and 507c, light and dark grey.
Good approximations in Humbrol would be 147 and 106, or at a push 147 and 67. As stated before, a good application of rust, grime and wear and tear will help with the overall look.