Hi - Our story is identical to yours re. our purchase of appt. in upper blocks at Green Hills (including watching progress on Eralia's website not realising it was the lower blocks! Would have been 'nice' of them to have made that clear).
Like yourselves, we found out in Sept. 2005 that nothing had been built (we were telephoning to ask if it was too late to choose the colour of tiles!). Eraliamade out that we were the only ones they had 'forgotten' to tell. We have since found many other purchasers were in the same boat re. not being informed. It was just a way for them to hold onto our monies for as long as possible.
We are fortunate enough to have found a great lawyer (we sacked our original lawyer who was obviously in cahoots with the developer) who finally took us to court last Summer to enforce our Bank Guarantee, and we received our monies back + legal interest. We feel very fortunate. We know of two other purchasers who received their monies back, but because they had lousy lawyers, did not receive any legal interest which they should have done.
Our lawyer was successful again last week for another purchaser from the upper blocks - monies returned with interest....finally!!
I do hope you have confidence in your lawyer, that he/she is independent (not recommended by your estate agent or developer). If you want to pm me with more details of your case, you are welcome. May be able to help with more info.