Thanks for your question.
On the basis that you own the garden land your neighbour cannot put scaffolding on your land without your express consent. If it does so it is trespass.
If you do not own the garden, e.g you are a tenant, then the neighbour can get consent from your landlord which will override your wishes.
If you refuse the neighbour can get a court order under the access to neighbouring land act.
I hope this helps. Please rate/accept my response.
It is difficult to comment upon time as it can vary in each instance.
You may be given the opportunity to put forward submissions to the court.
The court will not grant an order if doing so would interfere with your rights to enjoy your land or cause hardship.
If the court makes an order then you must comply with it even if during a time in which you do not want the scaffolding on your land.
I hope my answer has been helpful. Please can I ask you to take a moment to accept /rate my response so that I receive credit for helping you today, many thanks.