The UKHSA conducts a powerful survey of blood donors using Roche anti-S and anti-N assays.
These are published in graphical form in the vaccine weekly surveillance reports, but only in a rasterised graphical form. This repo contains code used to extract the anti-S levels from panels like:
we can then combine these two datasets in ratios according to the anti-N level in the age group:
(we digitise those data with Web plot digitiser