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

I thought that if you were positive in the past that you would likely throw up a positive in the future even if not infectious? (I assumed that is why they don't get you to re-test for 60 days after)

PCR yes. That could test up positive for up to 90 days (and even longer in some rare cases) on subsequent PCR tests. This is why you're advised not to take another PCR within 90 days of a previous positive unless directed to do so.

(If you're part of a study like the ONS study then they still want to PCR test you every month, but you anyone who tests positive doesn't have to isolate if they've already done a period of isolation in the last 90 days. As it happened in the two months after my daughter had it the ONS people came at times when she wasn't in, so she didn't get tested. Her most recent ONS test was November 11 which was 4 months after her initial positive test and the Nov 11 test came back negative.)

LFD should just be concerned with emitting enough viral output to be infectious. No problem taking those again at any point. If LFD is still positive 10 days on from the original confirmatory PCR I'd consider continuing isolation even though the rules say you wouldn't have to. (This is very unlikely for someone who is asymptomatic. If symptoms persist then I believe you need to keep isolating anyway.)

We did a few LFDs when my daughter tested positive, it went something like this:-
Day 0 - all did LFD before going to family party, daughter's test +ve (a surprise, no symptoms, etc), cancelled attendance, reported it online and ordered PCR tests, ordered food delivery, etc.
Day 1 - PCR tests arrive in post, do them, stick back in post box (day 1 of official isolation)
Day 2 - PCR results - daughter +ve, wife and myself -ve
Day 4 - LFD tests, daughter still +ve
Day 7 - LFD tests, daughter very faintly +ve
Day 10 - LFD tests, all three of us negative
Day 11 - freedom