Yes another persona complaining LIFE ISN'T FAIR because they can't access a benefit for married people, because they weren't married.
www.bbc.co.uk/news/av/uk-45348176/bereavement-allowance-widowed-mum-on-why-her-kids-are-penalised
If you want to be free and easy, stay as DPs. If you want the legal protection and benefits of married, get married. It costs a few quid down the registry office.