Making small change to application

I'm currently a first year social work student and I applied for student finance for 2nd year like over a week ago. At the time, when applying, when it asked where I'd be during 3 different periods, for the first one I put that I'd be on placement since my uni has us on placement in semester 1. What I didn't realise, though, was that because placements are, like, embedded into the course, I should've actually put that I'd be in university (at least that's what I read) since it's not like a real placement year.
Anyway, so I went to change that information today but it said the only way I could do it would be to print and fill out a form and then post it?? I'm just confused because the official video online that shows how to change your application, there it allowed them to change it online without needing to post it. I don't know, maybe it's because it's been over a week since I first submitted my application so it's further along in the process? But it also just feels unnecessary because for my issue, it's not even a listed issue on the form so what I'd have to do is write what I want to change on a separate document and then post it with the form?
This just feels like too convoluted for something so minuscule, like the ONLY thing I want to change is that during the period between September to December (or whatever the first period is), I'll actually be in university and not on placement.
Also, sorry to make a long post longer but I thought I'd add that right now, student finance is asking for evidence of my placement as a supporting document but I obviously don't have evidence as placements are allocated at around July time. So, I guess I also just want to know if, because I'm listed as doing social work, it's flagged somewhere that the placement is embedded and so they'll just carry on without me needing to upload evidence or am I actually going to have to go through the process of printing out a form that I'm not even going to fill because I'm going to have to write another piece of paper what I want to change and then post it?
Sorry again for the lengthy post, I'm honestly just ranting a bit but also I like to lay out all the information at the get-go. Thanks for any replies!

Hi there,
This evidence shouldn't be required as this would automatically go to update anyway for placements but you can upload a cover letter to your account for an assessor to review and correct on your behalf. Thanks, Jason

Hi Jason! Thanks for the reply (ᵔ◡ᵔ)
Just to clarify then, I would be okay with just leaving my application as is? It's just that, at the moment, it says I have actions to complete (uploading the evidence that I'll be on placement) and that my progress could be delayed if I don't. But because I'm doing social work, they'll know the situation and just carry on?
Also, sorry for the silly question, but what do you mean by cover letter? And would that go in the 'Upload supporting evidence' section or would I have to upload it elsewhere. Thank you!!