Honestly I don't see an issue with this. I could see it being an issue if the guy went around beheading all his kills for no reason or was just trying to piss off the community of which the beheading happened in, but he had a perfectly sound reason for doing it.
The fact is the target was dead, he needed proof and had no other way to achieve his goal than to take the guys head. If he wasn't under fire he would of took the body, but that was not the case and he had to go an alternative route. Would you rather read the title "Soldiers killed while trying to evac the body of a dead target" Or "Gurkha ordered back to UK after beheading dead Taliban fighter". Honestly I'd say the second option is a much better outcome for the soldiers along with their family and friends.
The fact is the target was dead, he needed proof and had no other way to achieve his goal than to take the guys head. If he wasn't under fire he would of took the body, but that was not the case and he had to go an alternative route. Would you rather read the title "Soldiers killed while trying to evac the body of a dead target" Or "Gurkha ordered back to UK after beheading dead Taliban fighter". Honestly I'd say the second option is a much better outcome for the soldiers along with their family and friends.