Odd Flywheel problem

The flywheel on the engine seems to be a Villiers Mk 1 - but the black plastic plate is being depressed in the middle. Once the Nut was off - I could see this flywheel is different to the other Villiers mk 1 I had as a spare.

Its slightly depressed in the centre - and has rounded edge to the three holes. The recess where the plate sits seems slightly smaller - when I try the blate cord plate on the other it fits fine - and the other is dead flat on the top - same as a Wipac - so the plate sits flat ?

That no is - R 345A80 CD HJ

Its dished in the middle - and does not appear to be through abuse. Its the recess size which odd - the black plate does not fit it - vet it fits the other Villiers mk 1 perfectly. Hence the flywheel nut is squashing in the plate and tightening up the cord groove.

Shall try to get it off next !