A nice little set. I'mguessing (by its lack of mention), that you are unaware of the additional significance of the Carausius? You'll note that RIC 143 lists the inscription PAX AVGGG and not PAX AVG. You can tell this is PAX AVGGG as the break visible is PAX A-[VGGG] istead of the usual PA-X AVG. Carausius issued these to try and get some legitimacy - the emperors in Rome were clearly close to retaking the island, so Carausius started issuing coins depicting them and with AVGGG legends (the 3 Gs being the 3 emperors - him and the two in Rome). This happened right at the end of his reign and so you can often tell just from the design of the bust.