The bedplate is 12mm ecocast. It is mounted in a way that I can adjust in situ then clamp it tight. I use a digital indicator mounted in the spindle and have achieved a parallelism of +/- 0.05mm across the table.
I didn't like the finish on the ecocast as it showed every little touch (just wiping swarf left marks) so I used a scouring pad + WD-40 to buff if to a uniform bright finish. This can be achieved every time I want to give it a quick polish.

I am undecided about z-limit. Will have a long look tomorrow.