I want to try applying tonight now but my husband can’t pick up the letters from HR until he is back from a work trip on Monday.
Am I correct in understanding the documents don’t need to be uploaded until before my appointment? So even if I book a super premium appointment tonight they do not need to be uploaded this evening?
The documents don't need to be uploaded until 2 days before your appointment... however, ALL the documents MUST be dated on or before the date you apply online, because the date you submit and pay is your official application date.
So you will need to be completely sure that the letters have already been written and are dated no later than today before you submit the online application.
Normally, we advise not submitting the online application until you have every single document ready and in your hands... so you can make sure they all meet the requirements. Because what happens if he picks up the letters on Monday and then finds that something is wrong with them and they need to be rewritten? It will be too late by then and the letters won't meet the visa requirements.
Can you ask HR to scan and email the letters to you today, so that you have them in your possession before you apply?