Are you an international student? If you are, I think you will have to as it will hold up your decision.
If you are a home applicant (i.e. Scottish or anywhere from the UK), that's extremely weird because I don't remember having to send any documents in to them. FYI, I applied to CompSci at Edinburgh and within 2 weeks of applying I got the offer. I have to do stuff about personal details now on the EUCLID portal but there was nothing I had to do for Edinburgh pre-offer.