You have to start somewhere and companys dont take on new rgis. I am new to gas work but i am studying all the time and learning everyday i dont need negative advicehave you been honest with your customer and told them that you havent done one before ?, its not really fair to gain your experience at your customers expense, they will have to live with your first "attempt" and may not be able to afford to put right your mistakes, take bens advice and work for a company, that way you can gain experience without ripping people off
To be honest I think that your being a new RGI is really your problem. The main reason companies won't take you on is because you've "learned" the trade over the Internet, and to any self-respecting company this "qualification" is worth less than the muck on my boots. If you want respect you'll need to spend time at college and get a proper City&Guilds NVQ qualification.