well, I can only speak from experience, but my little guys LOVE strawberries most our of anything in the world.
They also like dino treats, but I don't know if you can get them where you live? They're these little biscuits made from wheat and mollasses or something in the shape of dinosaurs, and Zander and Fergus go crazy for them , and they're sold in pet shops.
But, apart from that, they love dried fruits as treats too (for example dried apricot, banana, etc). I don't know if they're exactly nutritious for them or anything, but they love them.
Hope this helps
Enjoy little Jilly honey! Hope you get lots of treats!