Expenses before I went self employed

Hi all. First of all I'm sorry if this is in the wrong category! Secondly, I'm aware this is most probably a question for an accountant but I thought I'd try my luck here, as I can't seem to find anything on the HMRC website..

I have recently gone self employed (beginning of Oct) and I started using Quickbooks Self Employed today. I've connected my bank account, excluded all transactions prior to the beginning of October and sorted the rest between personal and business. However, back in April, May and July this year I purchased a desk, chair and computer in preparation of becoming self employed. As these items are solely for use of my business (I'm a graphic designer), I've put those transactions down as office supplies/equipment. They are the only 3 transactions for the business before October. Have I done the right thing? Or does it now look like I've started working for myself back in April as that's when I purchased my computer? Sorry if it's such an obvious or silly question but I'm completely new to this.

Thanks in advance!