Clearer warning message when changing pay reference period

Currently when changing the pay reference period it is not clear enough in the warning message that all notes will be deleted upon changing the pay reference period. When setting up a new payroll the reference period is always assumed whilst awaiting handover information. If then it needs to change it should be clearer that doing so will delete all notes that will then not be retrievable in the system.

A customer onboard is the first experience that they have of working with the bureau so it then looks awful to go back to ask for the handover information again. Copies can obviously be taken if it needs to happen but the warning message should be more explicit in what will happen rather than the vague "you acknowledge that data may be lost" which is what currently shows.