Pretty sure a company cannot deny you LSL. They can negotiate with you to take a
portion of your LSL, but if
you want to take the lot, they cannot deny your request. AL, certainly, but not LSL. At least, that's the case for us in WA.
Granting and taking of long service leave
An employer cannot direct an employee who is covered by the Long Service Leave Act to take long service leave at a particular time.
Long service leave must be granted and taken as soon as reasonably practicable after it becomes due.
The employee and the employer may agree when the employee will take long service leave.
Where an employer and employee have not agreed on when the employee is to take leave, the employer cannot refuse the employee taking any period of leave to which they became entitled more than 12 months before. This leave can be taken at any time that is suitable to the employee. The employee must, however, give the employer at least 2 weeks’ notice of the period during which they intend taking leave.
Source