This afternoon I replaced the two into one pipes to singles either side with slash cuts.
Already had the headers; got some pipe from Correy Wyatt's work (Metalworkx); made my own baffles out of pipe and some goldilocks pot scrubbers.
One of the baffles blew out the back and disappeared on a test ride. So made some more robust ones out of stronger pipe that sit just inside the flared end and can't move any further down the pipe.
The boys at Pit Stop mufflers flared the ends for free. Very kind!
Pretty happy with the result. Total cost $21 - including a new grinding disc!
[Mike - these are just a temporary measure until we sort something out to be done properly by you!]