It is a banded ring released by the clips if I remember correctly, obviously make sure all the pressure is out of the tyre.
A steel band maybe also under the outer cast band.
I am sure someone will be along soon who has taken these apart before
That is very interesting Moggs, sort of does not clear up Resto or replica !
As in the MK1 Spits flying now and the Hurricane Is to come I do like to feel they are restorations and not replicas.