A new theory is about to be published. As it is by respectable academics in a respectable journal, maybe there will be something in it?
https://www.bbc.co.uk/news/uk-england-dorset-67717015
Makes as much sense any any of the other theories, with perhaps better, albeit not truly explicit written evidence.
Why not? Seems reasonable enough
Also a good reason to use the giant as a flag device.
:o