[tsac]

The first issue you have is your company blocks downloads as you state. In company's that are that restrictive it might not be a good idea to attempt a by-pass of the rules.
Having said that, the Z3 is an OS10 device and if you want you can "sideload" android apps. Not all will work but most will.
Before doing anything I would check to see why your receiving a blocked message and insure your downloading correct. some company's have weird method and restrictions that create more problems than they think.

do a search for sideloading methods if that is your decision.