The Change Checker website has posted a blog about a rare 'faceless' Bank of England £10 note 'worth thousands of pounds'...
https://www.changechecker.org/2021/...s-of-pounds/To me this looks like a defaced note. As soon as the polymer banknotes appeared in the UK, people started rubbing out parts of the design with an ordinary pencil eraser. One of our tabloid newspapers even gave a demonstration on its website of how to remove the Queen's face from a £10 note:

I can't see how this could possibly be an error. If the sheet of polymer had a fold or crease in it, you could get a blank stripe across the note, and if a foreign object got stuck to the sheet as it went into the press, it could obscure part of the design, but the chances of it just neatly obscuring the Queen's face and nothing else is a million to one. I've written to Change Checker and told them I think this is a damaged note and worth only face value!