Nice bike! Probably only one set of mounts as you've got a small bike frame? You can buy various attachments that would allow another cage to be fitted - these look to be sturdy and neat.
You will need to measure the diameter of the frame tube. I use 'sidecages' - they allow you to pull out the bottle from the side - you might not be able to easily remove a bottle from a standard cage (esp. a 750ml one). Lezyne make good ones.
Thanks, yep 47cm frame, so would explain it. I'm sure I will need a second bottle once I get my distance up, so thanks for the ideas. Also a two pack is not a bad idea, my 9yr old daughter would love this, and her bike doesn't have mounts.