Sorry to hear about your SIL, Oopsminty, and thank you for letting us know about your experience, vampirequeen.
I agree that a lot more testing would be really useful, but I'm not sure how the lockdown would work if it became more widely available.
How would we know who had had it, and who was simply breaking the lockdown conditions? There would almost certainly be those who fancied going out and would pretend to have 'passed' the immunity test. Realistically, lockdown would still have to apply to everyone, which would probably cause resentment amongst people who knew they were immune, but were still unable to go to work, or to visit others.
Much as I can understand people wanting to know whether or not they had had it, in many ways, holding back any sort of home testing would seem a better option than having a situation where some were expected to observe the lockdown conditions but not others.
Tommy Robinson arrested. Police using their existing powers
What were the first ever records that you bought and when?
Lack of public toilets in towns.