I've had a printer here for a bit for testing and have just published a longish review if anyone's curious.
http://www.northlight-images.co.uk/canon-pro-300-printer-review/Biggest PRO-10 changes:
It's fixed margin/borderless problems of the PRO-10 for all media
Page length now up to 39"
A colour screen on the front
A bit smaller/lighter
Looks like a smaller version of the PRO-1000
The new Canon print software is rather nice to use
I've still got it here, so if anyone has any questions, just let me know here or email...
I live in Leicester in the UK, so have to thank Canon UK for giving me lots of stuff to do whilst our lockdown was extended!