Does Raven sleep on your bed at night? I am just trying to think of a way you can keep them separated for a while, but still give Prune her cuddles. It must be heartbreaking hearing her cry in the bathroom.

At least separate them during the day. Use the old towel trick...take a towel or cloth that Prune has been sleeping on and switch it with something similar that Raven uses. That way Raven gets used to the scent.

Just keep reassuring Raven. When I was a kid, we had one adult cat that stayed grumpy with us for quite some time before settling down...and it took a firm word or two.

How long had Prune been with you before the accidental introduction? They should be separated for at least a week.

And yes - Feliway can help a lot!