I left it tonight pretty much at this stage and tomorrow I'll move onto finalising U6 and U3, U8, U7 and getting TR8 in place.
If anyone could shed any light on my question in the chassis section it would be appreciated.
A small note on my measurements, I've been checking before every tack my alignment of each tube and the overall chassis to check for distortion etc, I'm happy to report I'm + or - 1mm overall on all my sizes, I'll check every thing again before I fully weld.
A final picture before I turned the workshop light out
Night all.