When you send things off you have to enter the barcodes on the test and the mailing box (assuming you're posting them back) in to a gov.uk website. That way they'll know which test is for who.
(Or am I misreading it and you did the tests there and then?)
[EDIT] The scanning of the barcodes on the grey bags is just so they can track that these test packs have been collected. They probably won't know by who, only that they should no longer be present in some stock somewhere. The scanning of your barcodes is just to fill in the records on the system to acknowledge that you have been in to collect a test kit as expected. At this stage the individual test kits won't be allocated to you or your partner specifically. That bit comes when you do the tests and enter the info on the gov.uk website.
When you send things off you have to enter the barcodes on the test and the mailing box (assuming you're posting them back) in to a gov.uk website. That way they'll know which test is for who.
(Or am I misreading it and you did the tests there and then?)
[EDIT] The scanning of the barcodes on the grey bags is just so they can track that these test packs have been collected. They probably won't know by who, only that they should no longer be present in some stock somewhere. The scanning of your barcodes is just to fill in the records on the system to acknowledge that you have been in to collect a test kit as expected. At this stage the individual test kits won't be allocated to you or your partner specifically. That bit comes when you do the tests and enter the info on the gov.uk website.