In the early virus stages where everything was unknown we needed a national lockdown, but a lot has now been learned. Only a national measures should be funded centrally.
I'm not sure why we need national vs local politicians arguing about funding. National politicians should set the framework to indicate when areas go into restrictions, and local politicians should implement the framework, take localised measures and fund them.
If people in an area do not take actions together to suppress the virus, then they should pay for the necessary restrictions because of their actions - it doesn't matter if legal or not. People in Cornwall or Norfolk should not be paying for people in Manchester behaving irresponsibly or deciding to live in a way that encourages transmission.
There should be no need to negotiate with Boris, he should just enforce the policy - Manchester should then implement the minimum measures (and go beyond if needed) and pay for any support they decide they should provide between themselves. If council tax and business rates need to rise, then that's the impact of local people's actions.
This would cause communities to self police.