You certainly can!
As with any air fill this is subject to your cylinder being in test.
We use a Partial Pressure Blending system to deliver our Nitrox Blends all the way up to 100%, Because of this we require your cylinders to be empty before we can fill them - If you can do this before arriving at the store it will save you a lot of time!
Filling the Cylinder from empty typically takes 10-15 minutes, once it is complete you will be required to test the cylinder (We have an analyser on site) and provide your Nitrox Certification details - All of this information is recorded in the Nitrox Log.
This is a HSE regulation and is beyond our control - No Nitrox certification, no Nitrox fill!