As someone who's very familiar with the public areas of the park I can genuinely say that I've never seen these around the park or even around the chained oak walk, although there may be some tucked away in areas zoned off to the public. Alton Towers in part due to it's size has loads of weird nooks and crannies that's accumulated over the years.
Alton Towers also has Flag Tower behind Walliams World/Dungeons, whilst widely known, there's very little pictures of the Tower, especially recent photos. Also does anyone know what the structure is behind the trees on the opposite side of the Hex entrance? I've been past it loads of times over the years but I only seemed to have noticed it behind the trees since about last September.
By the way, for future reference, You can embed links by pressing the chain link in the message bar (
like this) instead of just pasting the whole link in a post.