Hi Dutch - Americal Gryphon made a set (144 / 145) of 56SQN SE5s in 1/48, which included commentary (and decals too, I think) on Rhys Davids "I" with the blue dumb bell marking. The exact position and style of the markings are purely speculative, given there was no contemporary photograph of the machine around the time of the Voss fight. Obviously this set is well and truly out of production, but I have one in the stash somewhere, I think.
As for the Voss cowling, I have not seen markings available for this machine in 1/48, sadly.
Cheers,
BC