You really need to speak to Cumard about this, it could be that they have not yet released balcony cabins for sale.
We have already booked a balcony cabin for this cruise and we were told that the world cruise is fully booked so they may be full
The easiest thing to do is to log on to www.cunard.co.uk as this has full and detailed information about the ship and the cruise itineries. It is true that the first few voyages are almost fully booked as they have been on sale for quite a long time now but the wider 2008 program has only just been released. To check availability, you can use the live booking engine on Cunard's website - this will show what is available but don't book - once you know what's available, try telephoning cruise.co.uk and/or any other agent that you may usually use because they may have even better prices than those found on Cunard's website. Finally, Cunard's 2008 brochure has a thorough overview of the ship so pick one up from your local high street travel agent or order from Cunard online. Hope this helps.