and the crew did not have that as they had no n/w steering
Not technically correct.
It's considered good practice to drop the gear using the alternate system when you have a failure of one of the main systems. The idea being that the gear is a 'heavy' user and you don't want to overload the Green pump when it's supporting both Green and Yellow systems, or the Yellow pump for the same reason.
If you've lost both those systems then you have to use the alternate system anyway.
On older A320 family aircraft, using the alternate gear extension system disables the nose wheel steering.
There is a mod state to bring older A320 family aircraft up to the current spec which stops that from happening, allowing you to taxi clear of the runway.
My other point is the Blue system is powered by an electric pump, of the same size and strength as the elec pump on the Yellow system. In fact they are interchangeable, so if you're AOG away from base, without spares, you can swap the two and have three fully serviceable HYD systems again (top tip
It's widely believed (and demonstrated as true several times for me) that running the Yellow system off the elec pump will overheat that pump very quickly.
So, if the Blue elec pump is the ONLY pump keeping them in the air, I quite seriously doubt they would have been able to hold for three hours.
Therefore my take on this rather interesting incident:
They lost Green, lost Yellow, got Yellow back. Decided to hold for three hours (I personally wouldn't have, but I wasn't in command that day), dropped the gear using the manual system and landed safely. Finally resulting in them not being able to vacate the runway.
Also does anyone know when they dropped the gear? With the loss of two HYD systems, that would have put the aircraft in Alternate Law. Dropping the gear puts it in Direct Law, which makes the aircraft very sensitive to side stick inputs. That might explain the 'lurching' and sick pax. And they may have dropped the gear early to help with the fuel burn-off.
Checkboard: Too bloody right!!!!!! Almost threw my tea across the room shouting "just say Mayday and tell them to standby!!!". You could hear the Master Warning blasting away in the background for God's sake. What happened to Aviate, Navigate, Communicate?