You are safe.
The bailiff may only take control of goods belonging to the debtor.[1]
If your dad owes money and is living in your house, then you are not liable for his debt.
If bailiffs are threatening you with enforcement for your dad’s debt, then you can give a notice, or a statutory declaration telling the bailiff that you are the owner of the property and goods contained, and that you are not joined with your dad in the matter of his debt.
In more extreme cases, you can give a notice of an intention to apply for an injunction.[2][3]
Template Notice of Intention to apply for an Injunction
Send the Notice to the bailiff company and get a certificate of posting from the post office.
Give a copy of the Notice to the bailiff company by email and make a screenshot of the sent email capturing the time you gave it.
Send a copy of the Notice by multimedia text message to the bailiff to his mobile and make a screenshot of the sent text message to record the time you gave it.
Keep all screenshots for your file.
[1] Paragraph 10 of Schedule 12 of the Tribunals, Courts and Enforcement Act 2007
[2] Rule 6, Pre-Action Conduct And Protocols
[3] Section 3 of the Protection from Harassment Act 1997
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