I'm also finding it a bit confusing where non-UK situations are being talked about. The way things work does vary depending on location.
I'm not sure why apply to a community college if you have already decided to apply to a university and have a chance to do that.
They say you have preference to the course if you have a reason why your grades don't match expectations.
@NoWhereKnowWhere does it say that in this case you should disclose it in your personal statement?
If it was me I would contact the Admissions Office, without saying my name and only saying that I was thinking of applying for an access course. If they asked my name I'd say I'd like to make a confidential enquiry initially, since it's about disability. I'd refer to what you've said here. If I wasn't sure if the personal statement was the place to explain, I'd ask them when and how in the application process you should let them know about the reason. I'd also ask how the information would be used, who would be informed about it, and any other questions.
If you wanted to, you could also ask for the contact details of the university's Equal Opportunities Officer, and talk to them about your concerns. They should be able to tell you how it all works in practice and what you could expect.
If you're anything like me, having your questions written down in front of you would be a good idea.
Then you would have more information to base your decision on.