It looks like a healthy year of life can be valued up to £100k
qna.files.parliament.uk/qna-attachments/64754/original/PQ203081_072_073_074_079%2520-%2520Lib%2520Doc%2520-%2520Report.pdf
Less in tax payer cash, more as of GDP
It is not clear if the measures will end up saving many in nursing homes but if for example 30,000 die then they may be considered as having 1 year of life left before and that year was worth 0.5 QALY, which is 15,000 QALYs
Thus the NHS would spend no more than £300 million to save that life (e.g. in medicine), and if we went to £100k then it would be £1.5 billion
Extrapolating rather a lot (!!!), but if we consider the death risk as halving with each six years, but the QALYs as therefore 4, 11, 16, 21, 26, etc. for each group and then 15,000, 7,500, 3,750, 1875, 950, 475, we end up with something like 250,000 QALYs, which at £100k each (generously!) is only £25 billion.
Which is not that much compared to what we are spending. The problem seems to me that even if we had no lockdown, there would still be economic damage. I.e. Sweden has suffered just as much damage as everywhere else!
I'm not an economist so can't really comment on the effectiveness of what amounts to stimulus spending to keep the economy going and which is largely incidental to the fact of the lockdown....