if you do it that way it will need an sva test
A vehicle will retain its donor registration mark if either the original unmodified chassis or unaltered monocoque bodyshell and two other major components are used. If a new monocoque bodyshell or chassis from a specialist kit manufacturer is used (or an altered chassis or bodyshell from an existing vehicle) together with two major components from a donor vehicle, an age related mark will be assigned. The mark will be based on the age of the donor vehicle. An ESVA, SVA or MSVA test will be required to register the vehicle.
so unless you want a Q plate you will have to build it with the 100e running gear and then swap in the other engine and suspension later lol
or just use the 100e's identity lee