The choice is yours – there's no official guidance on this
The DfE doesn't have specific rules on this. That means that whether staff can pop a cork or 2 is at the discretion of the headteacher and the governing board.
Check with your local authority (LA) first if you're a maintained school because it may have its own rules.
Be sensitive to your staff’s needs
If you expect staff to pay for the alcohol themselves (see below), it's important that you make sure that nobody feels obligated to contribute. Remember that rising living costs will be putting strain on many people's household