Unfortunately there wasn't much budget for anything beyond the build. But the accessibility audit was lead by visually impaired people, and they did suggest what the benchmark was I had to meet and we iterated over that by me making changes and them flagging up what else needed to be done.

I also have the impression that there are quite a few people with older browsers out there because of the screen reader setup, and I don't think that's a good thing, but maybe it's a matter of doing what we're doing to older browsers in general: phase out support.