From CWS himself in this thread. I'm sure it'll all be fine once you get to the airport. Your checked in so that's the main thing, I certainly wouldn't worry about this.

10) IT glitch on Europe to UK boarding passes
Sometimes someone returning to the UK will not be allowed a boarding pass - with a message suggesting that a passport check is required. This appears to be an occasional glitch on BA.com and the App. It's annoying but at the airport nothing will be amiss, and a boarding pass will be readily obtained. See post 2 for one partial workaround.

https://www.flyertalk.com/forum/brit...ficulties.html