Wonder if there's anyone can shed some light on the origins of this problem.
The problem was sent to us by Dave Norton a while back but there was no FA date sent in with it.
Turns out that Ru Davies did the problem a couple of years ago but didn't write it up.
No big deal here, but it'd be nice to have the record set straight so if anyone knows Dave Norton, can they give him a shout for us - thanks.