mainly because it seems to be the next available course
Probably the worst reason ever to choose a course!

To be honest, a lot of the "courses" offered by suppliers and manufacturers are going to consist of two things.
1) how to set up the kit and switch it on and off
2) Very basic things like recognising what carpet/fabric you're cleaning and some very fundamental do's & don'ts
See these courses for what they are - a sales pitch to get you to buy their machinery & products. Don't get me wrong, most of the major suppliers supply perfectly good equipment etc but remember the purpose of the course - it's to get you tied in to that particular supplier. The by-product of the exercise is that you pick up some very basic knowledge.
You'll learn much more, and a lot more quickly, by "shadowing" one or two established, competent professionals who might be willing to let you come out with them for a day. Ask, there's quite a few guys on here who will do so.
The NCCA are probably best as your first port of call.
http://www.ncca.co.uk/