The Golan Heights wasn't part of the British mandate--I don't think it became an issue until the Syrians started firing down on Israel from there.
You are exactly right on the Golan.
I would never give it back either.
Works both ways and now Israel can fire with direct line of sight to the other side.
It’s funny though, if you go look up some pics of the Golan you will see border fencing and they are hilarious looking.
Israel on side and Lebanon on the other.