Hi Dan, before people can do the L3 NVQ they have to do a Level 2 diploma followed by a L3 diploma in Electrical installation. So this course might be the best link if you are wanting to get people to look at XS TrainingWell have you spoke to www.xstraining.com at all? They have a massive feedback thread here. Some guys are even sparkys now.
Online one available too. NVQ Level 3 Electrical Training Courses Online | XS Training - https://www.xstraining.com/nvq-level-3-electrical-training-courses/
Reply to the thread, titled "What courses do you recommend an aspiring electrician should take?" which is posted in Electrician Courses : Electrical Quals on Electricians Forums.