If this is anything like normal 4 wheel cars MOT I think the only way around the emissions tests come MOT time is to fit an earlier engine.
A friend of mine has a very fast Pug 205GTI and to get rid of the CAT he replaced the engine with a 405 M16 engine which was of an earlier precat fitment date and this is perfectly legal.
The MOT tester asks what year the engine is in my Plus8 every year so he can check it against the testers data, if you present a newer M3W with older emissions results I would say you run a high risk of failure as it will no longer be coincident with his data tables.
