Katy gives excellent advice to start off with the consumer’s office (why didn’t I think of that 🙄 ) – there you will get advice on your basic legal rights of where you stand with this developer.
The name of the office is OMIC – see previous thread further down page 1 of General Forum “Who is lady Sra. Bueno….”.
If you are not in the Marbella area, you will need to find out the appropriate Head of Dept. for Housing and Construction at your local OMIC office.
I also agree with Katy that this third block could be illegal. Am nearly sure in Spanish law that what is advertised constitutes a contract (i.e. the brochure on the development, the model of the development in the agent’s office if there was one etc.) is binding – and if the developer later deviates (in your case, Big Time!) he is legally in trouble. I suppose possibly it is a bit like our Trade Description Act?
But you and your group really need expert independent legal advice with a good lawyer that is in no way biased towards the developer.
Certainly, if your group can find a lawyer with whom you can all share the costs, it certainly makes sense.
Kick off with OMIC first, and go from there. Will send you a pm.