I did, and I'm pretty confident that the addition of the jessie-devel repository has taken effect, because the update output closes with the line "Ign http://apt.osmc.tv jessie-devel/main Translation-en"
Thanks for clarifying that the symbolic link message isn't an error: because it was the last line of output with no conclusive success/failure, it seemed worth mentioning, but perhaps I should have included the full output.
Regardless, Apt is still unable to locate the armv7 package. Perhaps I'm not your best test user, but I've tried to identify which repositories Apt is checking:
500 http://apt.osmc.tv/ jessie-devel/main armhf Packages
500 http://apt.osmc.tv/ jessie/main armhf Packages
And then a bunch of debian.org addresses