I'm not sure of I've hit the nail on the head but feel in the ball park!
Maybe Chloe isn't his daughter but a girl he has living there - like he had Charity in a flat - and has sent to play the part as part of a revenge to get Sarah as one of his girls. Kerry doesn't want him anywhere near Amy, so I'm thinking sex trafficking.
The surname Harris must be a red herring, Pierce doesn't have the resources and Kerry wouldn't be afraid of him.