Back to my mac - after yosemite

After upgrading my mac to Yosemite iClouds "Back To my Mac" feature has stopped working in one direction. I can view my work computer in Finder from home but I cannot see my home computer from work at all. I have tried enabling and disabling "Back to My Mac" on both, enabling and disabling on my Airport Express router and restarting that... but nothing seems to work. Quite annoying.

Any ideas?