Summit EP - unusual pressing gives us some clues

When I first saw the EP below, and spotted the layout of the label, I assumed I had chanced upon a mis-press. This is the EP I found, Volume 7 of the Summit "Top Pops" series, which happens to be the last one issued:

What's unusual about it? Well this is what my existing copy looks like, and indeed every label I've ever seen from this series (apart from volume 1, which was printed on green paper):

The differences are at once noticeable. There's a lot of extra text on this alternative printing, in particular the "45 rpm" inscription around the play hole, and the words "Rhythm Records" on either side. Those who know their budget EPs will know where these belong - namely, on labels from a different series entirely - "Six Hit":

My first impression was that this was a straight-forward mis-pressing, whereby the "Top Pops" text had been printed onto paper which already had the "Six Hit" text printed on. Using a bit of computer software, I have isolated out the two bits of printing below, so you can see where the various text elements come from. The one on the left just shows the "Six Hit" text, the one on the right the "Top Pops" text:

However, I got thinking about this and realised that this was not in fact an accident; this is an alternative edition of the EP. How can we tell? Well the clincher is the positioning of the words "Top Pops" at the top of the label and the catalogue number DTP 1007. Compared to the standard Summit label, it's clear this writing has been deliberately moved up, so as to fit neatly in the space available. If it were just an accidental overprint, then the two sets of inscriptions would have overlapped each other.

Now this gets intriguing. "Six Hit" issued their fifteenth and final EP around May 1965. This edition of "Top Pops" appeared in August, so was this some sort of formal arrangement to start transfering the "Six Hit" brand across? One can't help but notice the inclusion of the words "Six Hits" next to "Top Pops" on this latest label, and then there is the picture sleeve this EP was issued in:

I must have looked at this sleeve countless times, but never particularly noticed the wording on the back, "A product of Rhythm Records Ltd". Rhythm Records - whose name features so prominently on the "Six Hit" labels.

Apparently, recordings for the Summit "Top Pops" EPs were overseen by David Ede, and according to one knowledgeable contributor to the 45cat website, he was found dead shortly after this EP was released. Had he lived, it is probable that more EPs in this series would have been recorded, and we might have seen a more obvious union of these two series. As it is, there are just these clues in the printing of what I imagine is a somewhat rare edition of "Top Pops" volume 7, which point at what might have been.