The easiest way to see all the Sophos products available for iPad and iPhone is through the App Store itself. There was some news regarding Mobile Encryption provided by Sophos, but I didn't find it on the App Store.
After some searching, it appears there is: Sophos Mobile Control, Secure Workspace, Secure Email, Network Agent, and Partners.
I couldn't find anything about encryption which means it lacks a release. You will have to use Sophos Free Encryption on PC until something is released by them.