More that UK govt anticipated US first position and didn’t want to be beholden to it.

That definitely could be, although the Merck I'm referring to (which Oxford was about to sign a deal with) is German.

Jolly good they did that too as Merck is a US company, not an EU one.

And US companies ARE under an export ban.

So your point is?

Don't conflate Merck with Merck. There's two "Merck", one is Merck KGaA, which is a German company, and the other one is Merck & Co. Inc., which is the US company. These are independent entities today, they just share a common history by originally being a German company, of which the US company was splitted off during WW1.

The Oxford/Merck deal would have been with Merck KGaA, as far as I know. The US government would have had no means to apply export bans to a German-based company.