Thanks Bootsey for your assistance, answer and link to the advance mechanism. I replaced each part exactly where it came from, if you look on top of the barrel you'll see the notch on mine but not present on the pictures. But I'll read up and double check, thanks.
Picked up the 4 into 2 ($200) exhaust today. It was pretty dirty, bucket of hot soapy water, nylon scourer (got most of the tiny pitting), tea towel for drying and then chrome polish. It came up pretty well. It still needs more of the scourer as there are plenty of tiny pits, it'll do until I get it going, no idea what the chromer would charge (probably like a wounded bull).
Before cleaning
After cleaning
Still lots of parts to restore, dropped all the nuts and bolts in for re-zinc - 2 weeks wait.
So the plan is to first finalise the seat restoration with Chaser's foam, then polishing and painting with POR15 glisten on the alloy covers, true front and back rims and balance tyres.
I can start to see the end of the resto.