Q: Does annual leave need to be used up before LWOP can be used?
A: Unpaid leave is an agreed term, so there is no requirement for the employer to decide how they allow it.
Q: Could it be refused by the employer if the employee had over 6 weeks’ leave?
A: Yes, the employer is under no obligation to provide, so they could make a deal with the employee to take some annual leave while the business allows them to take some unpaid leave.
Best practice for the business would be to reduce entitlement before any other leave is provided.