yes that’s it passenger locator form only asks if you have been anywhere else which they would obviously check against your passport,you can fill it out up to a certain point then save the link which the gov e-mail to you to complete when ever suits you
day 2 lateral flow test(private not nhs)for landing back in the uk at the moment you need this for your passenger locator form which will need your ref code of your lateral flow test,but rumour has it all these requirements will be removed shortly