Squeezy

Hi, I live in the center of France and I have 3 silver birch trees near my barn*and I want to reduce the height in case we have strong winds and one falls on my*barn. 5 years ago my wife asked 2*local farmers to top them as can be seen in the first photo (they said this was the way). Now they need something doing as can be seen in the second photo but having read much about not topping birch what should I do please? I imagine if I just cut each large vertical say 20cm above*where they join the main trunk each will eventually send up a few large verticals again. Cheers, David