Bailiffs are not allowed to force themselves into your home to seize your possessions. So there will be no breaking down of the door or smashing of windows. They can however enter your house through an open window or door and can climb walls and fences both in your front and back garden.
If you answer the door to a bailiff they cannot force their way past you. They will try and get in by asking you nicely, tricking you into allowing them to use the phone, or try and walk in without pushing past. Don’t let them. Stand your ground and close the door before they get even close to entering.