[smudgie]

As a mother of "kids" of similar age, I would go down the Ulrika route.
She is a grown woman for heavens sake, why pander to her tantrums.
I never pandered to my kids tantrums when toddlers, this is the way they grow out of them. You ignore them.
As to Vanesse having more patience, she has only spent 5 minutes with Nikki so far, a couple more days of her immature behaviour might well change her attitude.