An optional UK prefix makes a lot of sense. It'd probably get used sometimes when it wasn't quite appropriate, and left out sometimes when it would have been, but so what? That happens already with the prefixes we've got - for example as someone pointed out, whatever this thread is, it isn't "Tech" - but no particular harm in that.

But no further splitting of the forum, please. Signposts are one thing, but barriers are very much an other.