i phoned dogtags and they want a full written description of activities and risks to show their underwriters so they can whistle this time.
I'm not surprised BT.
The snowshoeing option on most winter policies covers you for shoeing around waymarked trails in resorts which is a bit tame compared to what you guys are planning.
Surely it is in your interests that an insurer asks for a description of your activities so they can tailor your policy meaning they can't wriggle out of any potential claim. A long time ago I did a couple of overlanding expeditions across the Sahara. We had to provide a great deal of specific information to potential insurers for that as it wasn't run of the mill. Ended up with a more competitive quote and much more comprehensive cover for what we were doing.