[kevinbowman]

> where do you report lateral flow tests?

https://www.gov.uk/report-covid19-result

> if a lateral flow is positive...

I imagine that that report result site will refer you for a PCR test, although thankfully I've never personally been in that position.

[dTal]

That's exactly what happens. False positives with lateral flow tests are not unknown. In fact, if the prior probability of having covid is less than about 0.5%, you still have <50% probability of having covid even with a positive lateral flow.