I see they are Sibson Radio.
I think it's time under some circumstances for pilots to report base leg.
I see these confusions where i work and traffic wants to join final, even with AFIS they won't tell other pilots that an aircraft is on base leg, even when they can see it.
I see where i work that final traffic tries to push ahead of circuit base traffic. Then ensues a conversation by the final traffic asking where the other traffic is, only to be told it reported downwind, when air traffic can see it's on base leg.
Another accident waiting to happen, probably with a student, unaware of what's going on.