What happens if tenant doesn't allow county bailiffs access on set date?

Hi again all, been searching several threads and haven't found a concrete answer to my query.

For reference, before I confirmed the bailiffs appointment for december, as the tenant has started being very obnoxious and rude since the court hearing, I went to the court to hand in the slip and decided to speak to the duty manager about the section on the slip asking whether I thought the bailiffs might require assistance. After our discussion she said to me that she didn't believe I would need any assistance and said to leave that section of the slip blank.

So

What happens if tenant doesn't allow county bailiffs access on set date?

Or if the tenant isn't in at the time they visit?

What happens if, the duty manager was wrong, and the bailiffs can't proceed because of threat of violence?

Am I allowed to open the front door myself with my own keys to let the bailiffs in?

If the bailiffs cannot legally enter, what will I have to do then to get my home back??!

Many thanks for your help.