The interst rate that needs to be covered ny the Bank Guarantee was of 6% till 1999 when the General Building Act came in. Now the interest rate is the legal interest which has been during the last years around the 4-5%.
The Bank Guarantee needs to cover those interests.
You can ask for them now. Admninistrative fines can also work as a pressing tool. As if they failed to provide full guarantess according to Law, can be fined with a 25% fine on the must-be-guaranteed amounts.
I think you can success.
Regarding money back after 1 year delay in Malaga, you have got a string case. Just 5 or 6 months are consideres by the Supreme Court, an important breach of contract I usually ask developers for devolution of amounts, legal interests and expenses in these cases.
Maria L. de Castro
Lawyer
www.costaluzlawyers.es