Got my engineering head on and watched a video and couldn't quite see how he was getting them out but I realised that there is a gap about 8mm at the bottom. If I could somehow get something to expand under and slidehammer it would be easy. I did think about making a tool but that's madness when you want them out now but if the idea helps others I am happy.
I got a long M10 bolt so the head would sit under the bottom of the cush drive. 2 side by side would fit so I needed something to pack the difference and used a socket and then retained it with a couple of strong washers and a nut. With that holding firm I could then attack from the rear through the disc brake side and had a nice surface area to tap through. A few sharp drifts and they all came out and they annoyingly were clean as a whistle but I had to finish the first one with a hacksaw and gradually lever it out. Some minor damage will clean up ok but finally they can be get given to specialists to apply a good finish.
Horn is done in silver now and not black and oil coolers looks decent too.