OK, decision made, thanks for the input. Not taking the exams!
Most diagnostic companies offer a one stop shop, diagnosing electricity, gas, asbestos, lead etc. including termites.
I would be breaking the law if I diagnosed and treated termites. Although termites have been found in the Cher it is not a legal requirement to have a diagnosis. The owner has an obligation to inform their Mairie, it's not for me to dob you in.
So, I will stick with treating nuisibles, and diagnosis of xylophages, but not do the diagnostiques immobilier. It was a very useful course though and I've a better understanding of what's chomping away at your house!
By the way, if you've got an understanding of building/electricity/gas etc, and you speeka da lingo, there's money out there if you want to complete all the modules. It's not cheap though; 800€ for the training and 760€ for the exams and monitoring: Energy rating, gas, electricity, lead, asbestos and termites, (9,360€) but you earn between 300 and 450€ per diagnosis (each module). You must do a minimum of 5 diagnosis per year otherwise you'll lose your certificate. Diploma is only valid for 5 years.
I used http://odi-formation.fr/formations/diagnostic-immobilier/ based in Mérignac, next to Bordeaux Airport