Well, we had some luck. 2 adults and 2 kids in PE from LHR to DXB. I'm OWE and the others are OWS. We bid £155 each for an upgrade to business on a busy flight. The bids were rejected, but the flight was overbooked and we were all upgraded for free at check-in! We bid the same for the return. The flight was pretty empty in premium economy and business, but we were not upgraded.

It was our first time in PE on QF and we were really impressed.