UC - Mixed Aged Couples - effect on Kinship Carers

I wonder if you can help me.

As we know, from 15th May the criteria for mixed aged couples is changing. I have read that existing claimants can continue to receive PC unless they have a change in circumstances.

My question is this: Will this affect mixed aged kinship carers who are already receiving PC, who then go on to have a change in circumstances? For example, they have a child come to live with them and they make a claim CTC - would this be considered a change in circumstances or would the amount for the child be included in PC? (from 1st February).

Any information would be greatly appreciated, many thanks.

From 1st Feb can have money for dependent child in pension credit, so the mixed age couple stays on it