Put into other words, Annie is saying this (I think):
The employee transfers company on the same (or broadly similar terms and conditions) of employment. If there is holiday pay due to you, it should not matter whether you take the holiday before or after the TUPE transfer.
Any holiday pay (or other 'credits' due to one or more employers at the date of transfer) are part of the financial settlement directly between the two employers and don't impact the employee.