The problem with your math is that most population hasn't been infected...yet.
So lets toy with math, since you seem to enjoy it
The UK has 67,886,004 people according with wikipedia, in the first exercise i will calculate the 70% herd imunity
67,886,004*0.7 = 47 520 202 people infected
The second exercise i will calculate the 5% critical people
47 520 202*0.05 = 2 376 010 people in critical situation
The third exercise i will be calculating the death toll with the supposed 1%
47 520 202*0.01 = 475 202 people dead.
Question, can your country afford this?