....Friday evening:
Dark blue with I think it was AWK in the reg parked up at Cambridge services, it must have parked up when I was having some grub.
GF saw a light blue one on a driveway in Huntingdon but visible from the A14
(i was watching the road - didn't see it myself 
)Then I saw another light blue heading eastbound on A14
Sat:
Red one at Silverstone reg A16ALT
Sun:
Another red one at Silverstone on a Northern Irish plate.
A dark blue one
(F reg with a square front plate) heading westbound on the A14 (think it was between Kettering and Cambridge but I'm not 100%)