It depends if said 'mint new shell' has ever had an ID in its life previously.

If it has never been registered then you could legitimately probably transfer the ID as you will be using all the parts off the old car except the shell.

To be 100% sure, contact your local VRO (Vehicle Registration Office or DVLA) they may refer you to your local VOSA office but they'll defo be the ones to answer exactly what you can and cant do.