I don’t know about the UK, but in the USA the idea of “if you don’t want to be in photos published online, don’t be in public spaces” is pretty regularly upheld in courts. You don’t have an expectation of privacy in a public space.

You might have some recourse if another person’s video singles you out, but just being one of the several people in an airsoft video, where your face is partially obscured anyway, isn’t much of a legal standing.