Thanks Jonathan, I also found this document.:- http://www.caterhamracing.com/downloads/newsletters/superlight240702.pdf I was considering welding the tube up using a coded welder, adding damper mount gussets and then putting it through a Dye Pen crack test, but it looks like the latest tube is thicker gauge steel in a number of locations and has longer damper mounts- so probably worth 350 quid and peace of mind. Thanks for taking the time to highlight and document the issue. Rob.