I got myself a water level to check all the frame levels to make sure everything was straight and without twist.
It turns out the concrete floor was not quite as true and flat as I expected over its full length. So I made up a simple means of adjustment.
Now each frame is set up so it is the correct level with the greatest variation being under 2mm.
PIc shows the winch lifting the port side up so I can easily work on B/Hs that I bogged into place when the two sides were together.
The only exception being the B/H that goes in under the **** floor.
I made up a couple of spacers when fitting the b/h half in the port side. Using them should ensure the two halves line up when joined.