I’m sure the sub’s crew would also much rather get liberty at Rota than The Rock.
Makes me think there is some security or maintenance issue at play here. I wonder if the RN can pull a D5 Trident out of a tube there? Or maybe they are prepping for a covert mission and Gibraltar is just more secure for a pit stop?
The crew might prefer liberty in Rota, but would probably be more at risk of saying something about the sub mission there to the wrong person. Especially if Spain is at all Russia friendly, then spys are more likely.