Well given the way the zombies walk around Dartmouth blind and deaf to cars coming up behind them (even an Aero with a V8 and side pipes) I would guess it is to provide a mounting point into the back end of the "mascot" which will shortly be impaled on the bonnet if it does not get out of the way.

Its about right for a rear fitment...stops them landing on the fragile bonnets.

Everyone loves a Morgan. Even me, unless it's broken again.