Have experienced suction pump failure only once. First the DG stopped doing it's stuff, then after a few moments the AI gently wound down and fell over.
Fortunately I was in my local area with >40 miles visibility, but it was still quite disconcerting. If I'd been unfamiliar with the area or the wx had been less than perfect, I would almost certainly have declared a PAN. Much better to get help (and lots of it) early on, rather than push on.
Given your circumstances I'd be very surprised if the CAA took a harsh view of the event.