Sorry, no pictures but I wondered what they were - same size as current Cooper but clad in grey panel blanking. As a non-Mini driver I was curious what was being tested.
Might have been the new coupe Mini (or whatever it's called): I saw a metallic blue one today on trade plates traveling southbound on the M40 near Thame today. It looked quite tidy in a 'car gets sat upon by large animal' sort of way.