I use CollabraOffice and also muPDF. Collabra is great for viewing and some minor work, but I try to use libreoffice on my laptop running Debian for real productivity.

Just had a look. Much appreciated, thanks mate.

This is a shitshow. I use open source mobile office suite and Outlook continually refuses to open PDF or other documents as nothing is installed, so would I like to use their bag of shit instead.