Where to connect

I need to provide a cold supply to both a washing machine and an outside tap. There is a Megaflo in the same room as where the wm will be and where the pipe goes to the outside. I'd like to run a single 15mm to the outside tap and just tee off for the wm along the length.

Question I have is should I connect to the incoming main or to the balanced cold after the Megaflo's 3 bar pressure reducing valve that feeds all the other outlets to the bathroom?