The Guidelines are only Advice, and are not enfocible rules or laws. Not complying is not illegal, and you are not committing a criminal offence. Except the Government have given themselves discretionary powers to outlaw stuff on a whim. So whatever you do, you might falk foul of the Coronavirus Act 2020.
This Act allows the government the power to limit or suspend public gatherings, to detain individuals suspected to be infected by COVID-19, and to intervene or relax regulations in a range of sectors to limit transmission of the disease, ease the burden on public health services, and assist healthcare workers and the economically affected.
And that is where the confusion starts. You may be acting legally but not obey a new regulation.