After trying to defeat the two Cumans in combat multiple times and failing, I came to the conclusion I had neither the skills or the kit yet to defeat two Cumans. at that point in the game.
Because of this I decided to try the stealth approach, I crouched and set myself up directly behind Hans, not far, just by the small hillock so I couldn’t be seen. I then pushed the time forward to 1 am. It was very very dark.
Then crouching all the time I moved very, very slowly towards Hans and when just behind him, the untie option came up which I took. When Hans was untied he said ‘Follow me’ and this was only posssible by using the compass and following the A shield.
This all worked first time, without a hitch. I’m thinking that as the quest is so early in the main quest line in the game, it’s more about teaching stealth and that there are other options to combat in such situations. Either way, it seemed so much easier than taking the two Cumans on and then success in this quest opened up some good stuff.