When submitting a grievance letter to your employer after a significant event we would recommend making it clear to your employer that your decision to stay on should not be considered as you affirming the contract. Affirming the contract basically means that you are accepting the events and are still happy to work for the employer. This might impact your chance of success at a potential tribunal and the award they might give you.
Further cases on this topic can be found here: Lewis v Motorworld Garages Ltd (CA 1985) and Matuszowicz v Kingston upon Hull City Council (2009 EWCA Civ 22).
I will continue to work under protest, however, I reserve the right to repudiate the contract of employment should you continue to not observe your statutory obligations.