I've just had a look at the handbook for my Roadster. Under the section "What is not covered?" it says (amongst other things)
Damage caused by:
altering or modifying the vehicle -including the engine, body, chassis, or components - after the vehicle leaves MORGAN's control.
non-Morgan parts installed after the vehicle leaves MORGAN's control.
Note, that's far from the complete wording, check your own book, but it sounds fair enough to me.
Ian
