What about all the builders whe do plumbing electrics tiling plastering carpentry brickwork landscaping window fitting etc.... Do they have all the quals. Once again I'm not saying its right. It's just how it is. All that dodgy plumbing you see is builders, un clipped plastic pipe bouncing around under the bath. Flexi hoses looking like octopuses under the sink. And lovely compression fittings under floorboards. Has anyone asked them if their qualified before they started the job. At least you will know right from wrong.
Also I read level 3 plumbing books. I do anything to gain a better plumbing knowledge.