Pillar 4: serology and swab testing for national surveillance supported by PHE, ONS, Biobank, universities and other partners to learn more about the prevalence and spread of the virus and for other testing research purposes, for example on the accuracy and ease of use of home testing
It's a different set up/stream and doesn't seem to be affecting the service set up for those who need or request a test. Of course the government could commandeer the university and other labs that do these tests and insist they process tests from those who want/need one. But on balance both are essential- without the pillar 4 PHE ones we will not get the picture we need.
I haven't really thought about the £425 figure as I wasn't aware of it, but I can see that it makes sense to give people an incentive to continue supporting the important data collection exercise. In the scheme of Covid costs the sweetener is only in the order of hundreds of millions not billions