In an A3 fella, was cruising along in the middle lane as you came past at the Bagshot junction. Pretty much then stayed just behind you until I got off at 4.
Not quite sure how i sussed it was you. Just saw a silver R32 which you don't see often and remembered you had one and also trekked the M3. Looked up your thread and matched the private plate.
Full on stalker, you'll have pics of him getting changed at home next