You probably can, but equally probably (or even more so) you may not.Hmm, on closer look - maybe they're not designed for registered electricians?!? Can't put the NICEY logo on it can you??
I don't know what all the different schemes do, but I'd not be surprised to find out that all of them require you to buy their certificates if you want to issue certificates with their logo on and notify through them.
Plan B with NICEIC is to download the sample certs from their website, which they helpfully provide so that Joe Public can see what they should look like, open the .PDF file with a full copy of Acrobat, or any of the alternative PDF editors, and delete the "SAMPLE" watermark from each page....