Scooterotica

I'm at a loss with this one....mates px engined sportique, with SIP 10" to 8" conversion failed it's MOT on rear brakes not breaking evenly on the rolling road, MOT man thought it might be an ovalised rear hub. Cut a long story short.... ended up buying a new conversion kit from SIP, which included stud adaptor, shoes and hub, but this still didn't cure it, infact MOT man said it's now worse! I've checked the rear axle and that seems true. So, what else could be causing this?

Do the shoes just not need adjusting to the hub.
Lift back end up and spin wheel you should get a feel if it's working correctly. Remove hub and inspect shoes to see if uneven contact then trim with a file any high spots out. Keep putting hub back on and spinning to check then off and trim if needed. It maybe a long job depending on quality of shoes and hub.
It's ni on standard practice on lambrettas

just be aware if you are filing brake shoes, of the asbestos content- if any.

I should add, the rear brakes have been working fine for 2 years, since the engine was put in the sportique and has only covered 500 miles and passed 2 mot's.