If a product is designed for a specific customer, tested and CE marked but standards change before the last unit is delivered, is additional testing to new standard required?

The product should be CE Marked in accordance with the relevant directives. The manufacturer is ultimately responsible, irrespective if the customer is a one off, it is being placed on offer to the customer with the expectation that it will comply with the relevant directives, in this case EMC. If the product is manufactured outside of the EEC then the importer/distributor places the product on market/offers for sale. Should standards be upgraded, there is generally a “date of withdrawal” that the equipment would need to re-comply with beyond that date, if it were still being placed on the market.

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