No problem at all if you want a new registration plate, provided you don't mind splashing out the cash
To qualify for new build staus you are only allowed to use 1, as new ( Reconditioned ) Part
Normally engine or gearbox .... Keep invoices/reciepts .... DVLA will almost certainly check their authenticity
As far as I know .... You can still use second hand parts such as the Sierra steering wheel, switches & cowl.
All major running components must be new.