yes you're right! it's the female of Holopyga chrysonota (Foerster, 1853). It's quite common in Spain. Even if it has the same colour of the female of Hedychrum nobile, it has different nervures, different mesopleurae, different anal margin and temples. Also the colour is different. On the anterior side of the pronotum it becomes green or blue-green, in contrast with the rest of the pronotum. In H. nobile it has the same colour.