'12. 'Q' registration numbers
DVLA issues ‘Q’ registration numbers to vehicles whose age or identity is in doubt.
If this happens, any original vehicle registration number will become invalid and you mustn’t display it again.
To get a ‘Q’ registration number, your vehicle has to pass a type approval process.'
The car is a 1968 McLaren M6BGT which was built for Andreas Mohringer by Northdown Racing from a McLaren M6B chassis [no. M6B 5005] - the M6B being the version of the M6A Can-Am car for sale to customers.