Indeed, I was on that very flight. Boarded around 10:30 as normal, but the problem only became apparent as they where re-fueling.
I'm not an engineer, but I guess they need to open the fuel jettison valves to vent the fuel tanks to allow them to be filled. One of these valves would not open so they could not refuel properly. The engineers first tried to repair it but this wasn't successful so then they had to have a new one sent up from LHR which had to be tested first and then fitted.
The delay would have meant the flight deck crew running out of hours, so they swapped with the VS73 flight deck crew.
Due to the long delay, the crew decided to serve dinner whilst we where still on the ground at MAN (the IFE was also switched on), which was a bizarre experience sat eating dinner whilst watching a film but still on the ground! Extra snacks where loaded onto the aircraft for the actual flight.
We landed over 4 hours late into MCO at just before 20:00. Not sure which return VS flight that would have had an impact on?
In total we where sat on the aircraft for over 14hrs as they wouldn't let anyone get off whilst still on the ground at MAN.
Not the best VS flight I've had and certainly the longest delay I've ever experienced with VS the 14 years I'm been flying with them, though the crew did the best they could with what they had.
Regards
James Mitchell