Indeed am gas safe, the the course I did it did not teach much fault finding, you don't need the super skills for this job, you learn and get the experience after each job, with advice and research will help. you have to start somewhere?
Thats the problem!
You think that its reasonable to charge a customer while you are learning!
We think that if you dont know what you are doing then you should be doing an apprenticeship for several years until you are competent to do repairs yourself.