Sorry Tony I'm an idiot. It says "P.Con (Remote)"!

So a wire goes from this into the Blue "Amp Remote" wire on the sled?

Ok, this now leaves my "Antenna Remote Wire" on the dash (from the iso of the old head unit). This connects to the only blue wire I can see on PCAs tuner?

On PCA's tuner all I see is an antenn connector (fits fine) and the harness for connecting to the sled. Then a single blue wire on its own and a 3.5mm jack socket.