I may be being a little distrustful of human nature here but with this online booking of tests there is no requirement to verify you are a key worker or that you have symptoms.

The ordering of home testing kits went online at 8-00am and the 5000 available had gone by 8-02am. That means thousands were poised with their fingers on the button at 8-00am, Similarly the drive up tests were soon gone.
Call me an old cynic but I suspect that pushy mums will have got tests for Poppy, Anastasia and Quentin and husband Henry who is in finance and working from home. Just as with the panic buying in supermarkets the more savvy people will push in first irrespective of need.

Just wondering what kind of people will turn up first. I could well be completely wrong and it is the lorry drivers and school cleaners with actual symptoms who are there first.