From the extra information you've given, I would definitely recommend a vet check.

I wasn't trying to suggest that you beat your dogs or are in any way being cruel ~ but using punishment to stop a behaviour that you don't understand & for which you can't identify any particular cause, is not going to be any good at all. You need to find out what's causing Sophie's "grumps" so you can address the underlying cause, not just the symptoms.

I appreciate that Sophie's behaviour may disturb your sleep & that you are concerned as to why she's like this, & I fully understand that you want & need to do something to "interrupt" the behaviour if she won't or can't stop. But I don't think that pet corrector sprays, flicks etc are the best way. Would Sophie stop if you called her to you so you could reward a sit or something? Would she stop if you went over to her & asked her to do an incompatible behaviour like give a paw, or hold a soft toy? This wouldn't be interpreted as reinforcing the "grumps".

no, we are definitely not punishing her, she won't respond to anything. Shouting works but we don't want to do that, hence a noise maker, the pet corrector. then we can reward her for quieting down and distract her with fuss or a toy. I think the answer is a vet trip, it sounds like she's probably getting doggy alzheimers.

She doesn't appear to be grumping at Alice as she is usually sound asleep in a different part of the house.

Hi Jonathan also be aware that as some dogs age their sense of hearing/pitch changes , they hear less well and once familiar sounds can become scary and threatening .This is particularly so for dogs who have a degree of CCD , I think they also register sounds differently which was certainly the case with one of my dogs who started to bark at and be afraid of once familiar sounds.
Using things like a pet corrector can make the situation worse because they can startle a dog and make them fearful of a particular sound, then when the dog hears a similar sound it can react unpredictably through fear.
Far better to distract the dog with something like a familiar toy.