how have people trimmed the exhaust hole in the bodywork for SVA?

I didn't, just left it as it is. I don't see how it would affect SVA, I'm sure the guy who did mine didn't even go anywhere near it

Pete

Edge trim from these guys.
www.woolies-trim.co.uk

Use an old ali sheet / offcut. make a template of the hole. Overlay this to the ali. Add an inch or so right round and cut out / polish up. Rivet in place. The ali can be made to cover any raggy bits of fibreglass.

Exhaust Surround

Have a look on here - Sunday 29th.

Although as Pete says, it's not an SVA requirement.