Some further progress on the triple.
I bought cylinder cocks from Reeves UK, and the picture shows them fitted. In case I eventually install a mechanism to open all of the cocks simultaneously, they are in straight line, which necessitated making extension peices for the high pressure cylinder cocks.
The handles required bending to clear the pipework.
The cocks look a bit strange to me. Too big, and the handles are wrong. I am thinking about making a set from scratch. But that can wait.
The engine turns over by hand, but it is still a bit stiff. There was a tight spot which took many hours to locate. It turned out to be a valve rod thread which was about 0.5mm too long, touching the inside of the high pressure valve chest. Fixed in a jiffy.
I hooked up the engine to a small compressor at 30psi, but general stiffness prevented the engine from rotating. So I gave it an hour being rotated in the lathe at 200 rpm. It is noticeably more free, and getting very close to working. The valve timing is approximately correct (checked by my expert friends Thomas L, and Rudi V), but will need fine tuning at some stage.