I'm still trying to process the timeline on these Sol issues. I find the RIC dating discussion a bit frustrating. In RIC VI Sutherland stresses that the explosion of Sol coinage for Constantine occurs after his vision of 310. But you are right, he lists a date of 307-312 for these London Sol coins. In his introduction to the London mint he writes, "Two new types, on relatively light weight coins, appear, each for Constantine alone; Comiti Augg Nn and Soli Invicto Comiti, both with Sol, who at Trier makes a sudden impact on the aes ca. 310, and at Lyons certainly no later--a reflection of Constantine's vision of Apollo in Gaul early that year" (119-120). Is Sutherland implying that, of the 307-312 range, we should not consider a date before early 310 for these London Sol issues?
I think I've asked this same question about half a dozen times. I wonder if Cloke and Toone have light to shed. I don't (yet) own that book.