Reach 360 Overwriting Uploads from Storyline

Hi,

I'm using the (included tier) of Reach for the first time.

I've been uploading directly from Storyline and it's worked for the first couple of modules I've uploaded, but then Module 4 seems to upload 'over' Module 3 - i.e. it overwrites it as an update, despite being a separate named file in Storyline with different content.

I'm essentially stuck now unable to upload any more material as at least a couple of modules are suffering from this issue. 

Any experience of this from anyone, or any advice?

Thanks!