Numbers, Pages and Keynote files will not upload to my iCloud drive.

Other files e,g. pdfs seem to upload fine but the IWork files have a cloud icon next to them and say "uploading" when I hover the cursor over them - but other much larger files are uploading virtually immediately whilst the iWork files are still sitting there 2 hours later and are unavailable on my other computers/IOS. I'm using El Capitan (latest beta) and the latest versions of IOS and Pages/Number and Keynote on all devices.