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I've just renewed mine through them. You can fail like. Need to get 60% on your first try of the exam and they will fail you. They do push Worcester Bosch gear on you.
Reply to the thread, titled "Worcester Bosch G3 unvented course" which is posted in Plumbing Courses on Plumbers Forums.
We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.