Booked flight for 6th Dec in Feb 2012, 2 pax in C, first time with OZ.

Originally a 777, then a 77L and now been changed to an A321.

Now, the weird thing is when I booked my seats there were 3 seats left to pick from on the 777, when it changed to the 77L one of my seats changed to blank due to configuration.

Now it has changed to an A321 and one seat allocated, one not, but only 3 available seats in Business.

So, is this a blip? Have a huge amount of C pax cancelled or is this some serious overselling and chaos at departure gate? Is the aircraft likely to change again this close to departure?

Can anyone throw any light on this?

Thanks, Gordie