“ Some early manufactured Brooklands M3W's were made with pre 2014 chassis, as you say they were made from September 2013 so they would be.”
I think I got one of those at 11/50 even though my car was first registered in 2015!
That is why I said manufactured, not registered. There are quite a few M3W's that have sat about for quite a time before being sold. I know that by the time the Brooklands M3W's got into the 30's of 50 they were on post 2014 chassis for sure.