No. You are not required to use a law firm or claims company to make a complaint or claim for compensation.
You can raise a complaint directly with your lender yourself, and if you are unhappy with their response, you can escalate the matter for free to the Financial Ombudsman Service (FOS).
We are here to provide expert support, handle the process on your behalf, and improve your chances of navigating complex issues successfully, but the choice is entirely yours.