Seat Rails Revisited

A while back I welded some box section rails into the chassis to mount my seat runners / seats on.
Last night I added some crush tubes to prevent them, well crushing, and to keep the IVA man happy.
I got hold of a length of steel tube with an inside diameter of ~9.5mm (which is a nice fit for the M8 seat bolts) and a wall thickness of ~1.5mm.
I widened the holes in the rails out to 14mm, then put a section of the tube through each one, and fully welded them either side:

I then ground them flat to the chassis rails on both sides: