This morning I have 30 minutes to look after them, but they are working again...

Yes, all back to normal today after being pretty much unusable yesterday when each page load took minutes. Hopefully there's something obvious in the logs when you have a chance to look. Without doing any real telemetry yesterday (was having to fight other fires here, unfortunately) I can report that it was taking a long time to connect and then a long time to retrieve the page on top of that. Seemed pretty low level - maybe TCP or TLS - rather than within the application but that's just gut feel.