ORIGINAL: dgav407
You can probably make the later style (Evo) centre roll bar yourself.
I recall seeing lengths of the alloy pipe at Homebase (or B&Q) for a few GB pounds - they also had a cheap pipe bender.
Clive
I might give this a try. I'm not sure how the roll bar mounts on the evo though. I can see it is screwed through the bottom of the chassis but don't know if it is screwed straight into the roll bar or onto a post screwed to the chassis.