Welcome to EOS Titian,
Take a look down the General forum and you will find lots of information at 'Buying a property' on the thread 'Licence of First Occupation'.
Briefly, if the Habitation Licence/ Licence of First occupation licence has not been granted AND the developer is in breach of contract,i.e., late completion, then you are entitled to cancel your contract. The date on which the Licence was applied for is completely irrelevant, it is the date on which it is granted that matters.
It does seem that your lawyer is either unfamiliar with conveyancing law or working towards a satisfactory transaction for the developer.
If you go to 'Blogs', Maria de Castro the 'in house' lawyer ( I hope you don't mind that description Maria!!) has posted many invaluable articles regarding the law and your rights when purchasing property in Spain. I strongly advise you to read them.