Though our client didn't have any BG (nor original, neither a copy) the Administrators appointed by the judge (AACC) in the insolvency proccess of Herrada del Tollo mentioned in his individual creditor sheet (the one most creditors received by mail) that the amounts paid where guaranteed by a certain Bank.
This individual creditor sheet was part of the report issued by the AACC in 2009, and, as this report wasn't contested or challenged by the Bank, it was enforceable.
So, after claims and some negotiations, an agreement was reached, and the Bank paid.
There could be other similar cases. So, buyers should check their individual sheets and claim the Bank if it should appear any mention to a BG.