Earlier this morning the UK version of the Samsung Galaxy S4 Black edition starting receiving the update to the Android 5.0.1 Lollipop software, but as with all updates to newer versions of software the OTA's don't always get out to everyone immediately. Sometimes they take days to reach all the handsets in the specific region that they're being pushed out in, and sometimes longer. For those individuals that like to have things as fast as possible and may not have already gotten their hands on the Lollipop software through the OTA, it seems there is now a download of the OTA file available for installation and flashing.
A user on XDA developers (henklbr) has laid out all fo the instructions on how to grab the OTA file for your device, flash it and make sure your device is updated to the latest software without having to wait for the OTA to reach you on its own. This includes the installation of PC software called ODIN, which is used for Samsung devices when flashing software manually instead of pulling the software down from an over-the-air update. The XDA post also mentions that the software for the regular Galaxy S4 is available for download as well, which is also model number GT-I9505.
It's worth noting that these downloads are only suitable for the UK Black Edition and UK regular edition of the Samsung Galaxy S4, and shouldn't be used to try and install the Android 5.0.1 update to any other model of the device. In doing so you put your own device at risk and could potentially damage it, so if you don't use one of these models listed above then it's best just to wait until the correct downloads are made available or the OTA comes to your device officially. As a recap, users attempting to download and flash this OTA software will need ODIN installed on their computer first, and the software is only compatible with the UK version of the Galaxy S4 LTE Black Edition and the regular Galaxy S4 LTE. You can find all the instructions on flashing the software at the source, and as long as you follow things to the letter everything should be fine.