When can I make a complaint about an authority’s actions
If you think an authority has acted against the law, you can make a complaint. The complaint draws the authority's attention to what they have done wrong. Your complaint will be handled by the management of the authority, a higher authority that supervises the authority you complained about, the Chancellor of Justice or the Parliamentary Ombudsman.
A complaint may result in consequences for the authority, but a complaint alone will not mean that a decision you are unhappy about will be changed or that you will get compensation.