That’s exactly what I was trying to understand too. In this bay the physical Blue Badge isn’t used at all; the CEO checks the virtual Blue Badge resident permit on their device. If it shows as live, that’s the immunity.
In my case the BB itself was fully valid, but their system misplaced my uploaded documents, possibly onto an old permit. Victoria from parking services found them, confirmed the badge was up to date, and then authorised the renewal while I was on the phone. So the virtual permit should have been showing as valid at the time. The failure was entirely on their end.