UK post-arrival covid testing

[Badger18]

I'm wondering if I can use the day 5 test as a pre-departure test, which would require a turnaround of 1-2 days max and a proper certificate rather than just an SMS.

 

I realize not many people will be taking these tests now, but does anyone know how the system works?

[Upnotover]

Day 5?, I thought it was day 2.  In any case all the providers are listed with their contact details on GOV.UK and it's likely better to ask a couple of them directly how and when you will get your result.