I don't think it can be rationalised. I suspect most trad buyers buy one, and keep it, or get rid quickly.
So they are irrelevant going forward. But the ones in this group who do matter are the ones who buy another or trade up. This group are not likely to be looking at rivals.
I think the CX programme is to suck in a new group, which is what its doing.
The Aero and M3W did this, and some of those buyers then eventually bought trads.
DaveW '05 Red Roadster S1 '16 Yellow (Not the only) Narrow AR GDI Plus 4