I used to be a compliance officer and much of the certification is mandatory. Are you sure the manufacturer wasn't compliant? I never dealt with bicycle certification but a range of products some with greater safety issues and some with far less and the certification was pretty much mandatory for most of them. Some had an allowance for self-certification but often required sophisticated test equipment that only a test house would have anyway. Some minor products like small torches required certification just to prove the switch didn't create RF interference.

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Many of the chinese bike manufacturers clearly show their models are certified with CNAS logo's etc on their site. If you are reselling such bikes then you are pretty much good to go in many markets. Someone like fuji-ta probably has certification available for a wide range of models. Smaller back street bike manufacturers who produce lower volumes and more likely to create an inconsistent product may not. That certainly was my experience of chinese manufacturers. Some would only certify a product with a concrete order to go with it.