frankv:
My point about the 14 day clock related to the time during which you might pass the infection on. I thought symptoms started about day 3. But likely there would be a bell curve of probabilities for that and the 10 day infectious period. Whilst I accept that someone is still infectious 50 days later if they're in hospital, they aren't going to pass it on. So I was only considering the time someone in the community would be infectious.

I feel thats valid, as the only issue we now is CT. A new CT case means there is another case that we cannot locate. If the 4 week lockdown is good enough to capture most infections, but not all, all our testing now will be those leaks, once Level 4 ends. They should be small leaks, scattered, and all the 6000 test capability will be focused on that. Whether 4 weeks should have been 6 or 8, is probably down to 4 will be good enough to suffocate most off the virus. The extra benefit of the 6 or 8 week option will be small, the effect on the business will rapidly escalate. Diminishing Returns.