We employ a number of staff on an as and when basis - to cover for staff on leave or at busy times of the year when we need extra staff. We currently use an "as and when" contract.

Is this ok and can you provide an up to date model contract for this type of employment?

We have also been advised it might be better to use a "zero hours" contract - can you advise on this.

Also whats the best way to calculate and pay annual leave for occasional staff whose hours change from week to week?