Maybe stack some winny w/it. Winny may help you avoid the progesterone receptor probs often associated w/deca use. Though, it's no guarantee. Maybe somebody else has a different take.
RU-486 seems to be the only "sure" way as winny is very much hit or miss. You're in europe, correct? It may be easier to come by there. In the U.S., it's kind of scarce. As for proviron, don't know what it would do w/progesterone.