No expert on this as such ...bought an A40 Farina 62 at auction but from EU side of Cyprus therefore we paid no duty as it is within Euro free trade zone and all that .... straightforward really..
if you have the original country logbook normal course would be you must get MOT first or you can't register it...
can do via engine and chassis number at local garage ..then take to nearest DVLA office (if any still open anywhere) for vehicle inspection if they tell you to...
complications are now if pre 1960 no MOT needed otherwise they will then issue you with new age related reg and red log book....
My 68 cafe racer was us import and I just got age related plate but was imported back in 74 ...good luck...