RS1,2and 3 to BR12

[brainbug007]

Arg I thought I had this bit sorted but I've gone to fit d12/13 and found that the whole assembly is out I know the d12's should come down and sit on the outside of the rs7 part but mine is 19mm out so one d12 would have to sit on top rather than the side and on the other side it has a gap. Will I get away with just adding a small section of box tube between rs7 and d12 to plug the gap and just weld the other d12 on top rather than the side?