Chat about Novel Coronavirus - 2019-nCoV - COVID-19

That isn't what the guidance says for thier staff

It is though. If you test positive on the 8th, 9th or 10th day then your isolation continues (since it continues to the end of the 10th full day without satisfying the early release criteria).

If you test positive on the 10th day then you still continue the isolation to the end of that day, but then you just need to continue the daily testing and not return to work until you test negative. It doesn't mention isolating past 10 days.

"not return to work" is not the same thing as "isolation"

Ref: https://www.ouh.nhs.uk/working-for-us/staff/covid-staff-faqs-self-isolation.aspx

You must continue to take lateral flow tests on day 8, 9, and 10 of your original isolation period. If any of these are positive, you must isolate and wait 24 hours before taking the next lateral flow test
If the test is positive on the 10th day, you should continue to take daily tests and must not return to work until you get a negative test result