Thanks so much for that it's going to be REALLY helpful!
Unfortunately I looking at the diagram looks like if I remove the bolt it should just slide out but it doesn't. I have sprayed dismantling oil and the tube slides freely on the shaft but just won't budge. I'm scared of breaking something trying to knock it through from the right.
I believe I'm working on a 79
The 2 bloody brake shoe bolts have snapped too, need some extractors.