You can find out the registration details about the vehicle here:-
http://www.taxdisc.direct.gov.uk/Evl...vent=link.next
and check driving licence validity here:-
http://www.direct.gov.uk/en/Motoring...ns/DG_10037875
http://www.direct.gov.uk/en/Motoring...ons/DG_4022499
http://www.direct.gov.uk/en/Motoring...ons/DG_4022619
It depends on how long the driver has held a licence as to what 'groups' are included (see the licence):-
DVLA cannot give legal advice on how vehicles are classified but, generally speaking it depends on the weight of the vehicle or the number of passengers it can carry.
Any queries should be directed to the DVLA on 0300 790 6801 and lines are open Monday to Friday 8.00 am - 8.30 pm and Saturday 9.00 am - 5.30 pm.