I don't think it was a case of queue jumping - he was simply going the wrong way around the circuit!
Sounds much more likely given your first post.
I am assuming there was no AT? If you hear another aircraft joining in my view it is well worth saying explicitly where you are and what you are doing in the circuit because it at least means there should be two pairs of eyes looking for each of you rather than just you looking for him.
Viz: G-XXXX is also in the circuit, currently crosswind, about to turn downwind (tight or wide as you like), not visual with you this time.
Subject to viz etc I am always a bit cautious of steaming on without seeing traffic that I think (based on their position report) I should be able to see. Call me an old women but if I cant see them I might ask them for a position update and even consider adjusting my height in the circuit by a couple of hundred feet. People seem to think circuit heights are sacrosanct but I would rather adjust a little than increase the risk of meeting another aircraft going the wrong way.