Dave you make a lot of assumptions. Let me start with the most glaringly obvious one:
“But surely almost anything can count as an 95% effective vaccine when the mortality rate for a particular virus is less than 0.07%,…”
I have not seen this claim substantiated anywhere. The mortality of this virus is between 1.5, and 0.5% never seen such a low figure. It is also very variable and age and country dependent. In any case it is not just about mortality is it? Shall we ignore the 5% of those who get it who have severe illness and are admitted to intensive care, or the 20% who get milder symptoms and who are either debilitated or self isolate to prevent more people being infected. The high infectivity of the virus is what the vaccine is measured by not the mortality rate.
“…..ways to strengthen our immune systems, with healthy eating, exercise and socialising in the sunshine to grow Vitamin D,”
For an effect on good diet on the immune system you have to really be malnourished. The average citizen of the west will barely suffer such a degree of malnutrition as would affect their anti-viral immunity. The major effects of exercise and a healthy balanced diet are on such things as lifestyle illnesses including obesity, diabetes and high blood pressure and heart disease. Socialising is good for mental health but not during a highly contagious pandemic.
“…..whereas vaccines rest on an assumption that all the rest can be avoided with a preventative magic jab.”
It is not a magic jab it is a very carefully manufactured vaccine which produces antibodies against the virus and thereby reduces the number of individuals susceptible to the virus. The good diet and the vaccine are additive and the one does not exclude the other.
I agree that a virus mutation can mean that the virus is adapting to its new host in which case it may well cause it to become less deadly in time. To me at the moment the main significance of the mutation is that it is a measure of failure of the government policy of lockdown, i.e. that the lockdown is either not being observed or is poorly implemented. After all, the measures were designed against a highly contagious agent, and if it is more contagious it means that the measures were not severe enough.