piece of cake, done it plenty of times. But it does depend on wether you get the jobsworth in your local DVLA office (i know who to avoid in the Portsmouth Branch!)
My approach is this
1, Get the MVT to verify it (or IMPS etc)
2, MOT it
3, Insure it
4, fill in form V55/5
5, Take it all to DVLA with your £55 i think it is now
I tell them its a barn find that has been restored, that was originally imported by the British under the lend-lease agreement during WW2 and was released from the British army in the 60's. That way all your paperwork should match up i.e numbers etc and there is no import stuff to worry about.
You then get a date for inspection so they can check the numbers and the vehicle is roughly what they think it should be.
Job done.
Unless you get the jobsworth, then they may ask for a letter from HM custom to sy they have no interest in the vehicle for tax reasons. the problem you have then is Customs in Dover are not interested in writing such a letter as they say you dont need it!!! and so it goes round. this has only happened to me once and when i returned to DVLA they processed it straight away!!!! MAD!!!
Worked for me many times on many WW2 vehicles.