will the revenue not suggest that we are doing this to separate sales so that we dont hit the vat threshold.
There is always that danger which is why my original suggestion was separate tills, preferably with key access only available to the appropriate waiting staff. You should have a written agreement in place setting out the exact conditions for the businesses you are operating and how they intermingle to assist in heading off this approach by HMRC.
How would this work on the receipt side. for example the till receipt will need to have a vat number. therefore most likely my clients, but who ever reads it will assume that it includes the vat on the food. hope that makes sense.