Haha - maximum confusion!
From me, the following points speek for melisellensis:
- There also occur orange-bellied siculus on the mainland but in these cases, also the flanks are orange. The specimen on the questionable picture has light flanks with fine dark pattern.
- In orange-bellied siculus, the orange colour rarely reaches the throat and there are never orange upper labials. "Our" specimen has bright orange upper labials.
- Our specimen has a fine dark pattern while in siculus campestris there are usually big dark blotches.
- The light dorsolateral line combined with the rather small and short head also speak for meli (although these characters fit also for female siculus).
- The well defined blue outer belly scales also speak for melisellensis (rather pale and blured in siculus, if present).
Soft characters, I know...
Finally, for your please a nice shot a colleage has done on Cres in April:
http://lacerta.de/AS/Bildarchiv/IMG_9614HD.jpg
Cheers.