Cannot use force to gain entry to a property. Walking in through an unlocked door or climbing in through a window is acceptable, however, forcing their way past someone at the door is not acceptable. The only exception is bailiffs acting for the Inspector of Taxes who can apply for a warrant to force entry (but this is rare). Once inside they can use force to open other doors and can return to the property again (using force if needed).
Bailiffs recover money that people owe their clients. Bailiffs do not generally have the right to force entry into your home. However, they can gain 'peaceful entry' if you let them in, or they enter through a closed but unlocked door or open window.