Funny, I was out and about with the family today and saw several RIBs being towed places.
One heading up the A3 behind a Jeep about 09:30, a Blue one in Sainsburys Fareham petrol station about 11:00, and another very smart Blue one with Coastguard on the side, on a trailer, on a flat-bed lorry, going along the M27 towards Fareham just before lunch. (As you can tell I'm not very good at Identifying Ribs)
Got me all annoyed I didn't have mine hitched up on the way to the slip.
By the way, wasn't me on the M5/M6 either