David Fletcher sortof addresses the issue briefly at at 2:56 in this video. https://youtu.be/XXH02YX7gxY?t=176

It is worth observing, however, that the 'terror' only lasted a short while. The idea of dealing with armoured vehicles wasn't new, armored cars had been around for years. What was new was the fact that these things could take the short route over the terrible ground of no-man's land and their weaponry was a tad bigger. But in terms of killing them, AP ammunition, even for rifles, started being issued, and artillery, of course, were more than happy to engage them with direct fire. So, after a while, it wasn't the tanks themselves which were particularly terrifying, only the question of if the defenders had enough firepower to stop them, a question which applied to any attack.