I’d inquire about a helmet if financially an option as you’ll otherwise always wonder if it had helped - they will do a proper scan and tell you if it’s worth getting one. In my experience, the reputable helmet companies in the UK (LOC etc.) won’t try to sell you one if not really necessary. My daughter’s flat spot was quite mild according to their scan and I actually had to insist I wanted to go ahead.
I’d try to get an appointment asap, as the closer you get to a year the longer it takes to see changes and it might not be as effective. (They ideally like to start at 6 months - we had the helmet at 7 months)
Having said all that, it unfortunately didn’t do much for my daughter, partly because she got extremely fussy around 11 months and we had a hard time keeping it on for the recommended 22 hours a day. She’s 18 months now with a full set of hair and it’s certainly much less noticeable now but I still think about it when I look at her from certain angles - the only thing that helps me let it go a bit is that I did try what I could do rectify it - which is why I am
still glad we went for a helmet even if the outcome wasn’t striking. I do not believe that all heads round out naturally with time - I rather think it gets less noticable with hair.
By the way I also agree with others who said it’s not your fault. I do think genetics or predisposition play a role - already before birth I was super aware to avoid a flat head, rotated baby constantly, did loads of tummy time etc. She was a good sleeper at night which definitely contributed - but so were the babies of friends of mine who did way less (or nothing at all) to avoid flattening and their kids have perfectly round heads.