Hey all, might be able to provide some degree of insight, i was paxing on board.
As usual, media over-sensationalised the whole thing. Gradual decompression - felt my ears pop and noticed nearly immediately after that the exit signs lit up. I'm familiar with Airbus systems so this is when i knew we had decompressed. About 30s later felt the engines roll back and heard "Emergency Descent". Rubber jungle about another 90sec after the announcement. No shakes, shudders, sounds or smells. Just a standard descent with the boards out - as expected.
All ran rather well, crew followed procedure, pax were well informed, I managed to avoid the que for the service desk but ground staff seemed to be coping well. All in all a fairly tidy operation from what i could observe.
As for the Fault? No idea. We were only level for what felt like about 10-15min (wasn't timing so it could've been more) before climbing back up to FL170. Also looks like we had a fairly northern flight plan prior to the diversion too. May suggest a Non-ETOPS profile. Perhaps there was an MEL on one of the Eng Bleed's or a Pack Flow Control Valve. Both of which are non-ETOPS and supplying pressurisation with a single bleed source. Operating bleed fails, do the dive, fire up the APU and divert at a level below APU-Pack operating altitudes.
Can't say specifics for the A330 but it would fit the mould for my type. Obviously this is all speculative.