Hybrid HMV 45s

Donald Trump's recent less than overwhelming rally in Tulsa brought to mind Gene Pitney's 1963 smash hit '24 Hours From Tulsa', which in turn made me wonder why the UK 45 came out both on the black United Artists label and a blue hybrid HMV/United Artists label. The US United Artists label was formed in 1957 to issue movie soundtracks but by the earlier sixties it had begun to release pop and soul records (Marv Johnson for example). In the UK these were issued on Decca's London label but distribution was taken up by EMI in 1961, who chose its His Masters' Voice label as the host.    https://www.youtube.com/watch?v=zugy2rkSM7g















Presumably there was pressure from the US end for EMI to set up a separate United Artists label in the UK and as a compromise EMI agreed to a hybrid HMV/United Artists branded label. This was similar to an agreement with Verve, which had issued many mostly jazz LPs on a co-branded label. The new hybrid HMV/UA label featured records by, among others, the Phil Upchurch Combo, the Highwaymen (who gave them a UK number one with 'Michael'), Al Caiola, Kenny Dino, Jay and the Americans ('She Cried') and Steve Lawrence. The biggest name, however, was Gene Pitney. He recorded for Musicor, which had a distribution deal with UA in the States, and his records appeared on London, HMV, the separate United Artists label and, later, Stateside, when Musicor's US distribution deal changed (I assume).    https://www.youtube.com/watch?v=EYPqEczbFHE
The curious thing, however, is why '24 Hours From Tulsa' appeared both on the UA imprint and the blue HMV hybrid label. It was issued many months after UA became 'independent' and carried the United Artists UP label number, rather than HMV's POP series number. Was this because sales were so good that they ran out of labels? Seems hard to believe, but if anyone knows the answer please put a comment.
Here are a few more examples of the hybrid HMV/United Artists label.

Some LPs appeared on the dual format, including the first albums by Gene Pitney and the Highwaymen.

Here's the LP label design, which again is similar to the HMV/Verve LP label.

The hybrid HMV/Verve had only a few 45 releases. Here's one of the best.   https://www.youtube.com/watch?v=3IoGehtkQ2M