With the kind help from phil from talon I have found out where my error is. He kindly popped down tonight and found it is a error in my bottom rails. It is 5mm and I just missed it,
but it is just adding up as I go further in the build. Anyway as the mx5 based chassis pack was from him he has taken it away and I have asked him to fully weld it up.
I now feal a bit of a failure I wanted to do the whole thing myself, but at least now it will be right. He did say my welding looks good so at least thats something.