"I find the idea of him wearing a red-dyed outfit somewhat bizarre. Presumably green would have been a more effective camouflage in the forest ... ?"

In medieval England a 'forest' was a hunting preserve and a place for deer - not a 'big wood'. Some forests were on open heathland or moorland and some forests were wooded - but this was just coincidental.

Nevertheless, I would have thought that red was not particularly good camouflage on a moor or a heath!