I did a factory reset and it was still not working until I removed the "app link" from my phone's home screen, cleared the cache and then re-entered the URL 192.168.5.1 into the browser again. It is all back to normal now. Yeah!
Maybe after the firmware upgrade I should have done the same process of clearing the cache, etc?
I'll try it again tomorrow. I had a bit of a freak out when it stopped working and I have shoots in the morning so I figured best to do a factory reset until I get better instructions from Alex or Chris on updating the firmware..