Bailiffs can call between 6am and 9pm for most types of debts, but at these extremes, it can be considered unreasonable. The law is set out in Regulation 13 of the Taking Control of Goods Regulations 2013.
If a bailiff is banging your door in the early hours and it is causing you or your neighbours alarm or distress, then the bailiff is causing a disturbance and commits an offence under Section 4, Section 4A, or Section 5 of the Public Order Act 1986. Call police on 999, then tell the bailiff this has been done, then get your mobile phone camera or a video camera ready.
Under no circumstances open the door to the police - even if they ask you to. When they turn up, you should speak through a window or letterbox. Opening your door may get you into serious trouble if the bailiff or police get inside your property.
Politely say you are unable to open the door until your lawyer has advised you to do so, and he will not be available until normal business hours. Remind them that if a police officer places a person under duress to open a door to a bailiff, then nothing that follows is valid.
Capture the conversation on video in case the police officer slips up in the heat of the moment and threatens to force your door open. That opens up a complaint against the police officer with the IOPC for misrepresenting his powers. You can tell the police officer you will make a complaint to his superior officer or the IOPC.
Ask the bailiff to "quietly leave the property" and state that you "do not do business at the doorstep." Repeat that statement again and again with the camera rolling.