I'm not sure exactly, it's one of those weird extendable ones. I think it's 18 or 20 cm at its shortest. And it's technically a loaf tin, not a bar tin, I just get the two confused. A bit more than 5 a bit less than 10 wide.

Eggs would probably help it rise! Gluten-free cakes in loaf tins struggle anyway, they often end up sunk in the middle, and eggless ones especially so - this one was shallow in the tin and didn't rise very high, and so has a relatively good stability.