1) Ensure your product is EMC, safety and RoHS compliant, that it has the CE mark, and that you have all the necessary documentation to back this up (technical file, test results etc).
2) Everything else.
Are there any one stop shops or services in the UK/Europe that will help with this that are affordable for low volume production?
Well, "affordable" and "low volume" are kind of vague.
I provide this kind of advice/service as a business, so yes, you can fine people providing a "turn-key" solution to get CE.
Most test-labs would provide this as well.
Costs really depends on the product.
If there's only RoHS, you'll get away with 1k for getting some documents written.
If you product is rather simple:
For EMCD, add 5k for accredited testing
For LVD another 5k for accredited testing
RED adds 5k for testing to EMCD+LVD (the RED includes both).
Whoever supports you with expertise to draw up a CE declaration, choose the right standards and compiles the documentation, will also want his time paid...
As a ball-park figure, just add half of the costs for testing.
The more test you need, the more thought goes into choosing the right ones and the more documents need to be written, checked and archived.
Please keep in mind that these numbers above consider testing in accredited labs.
Depending on the quality of the documentation you get from your suppliers (eg. test reports for your radio module), there's quite some variation in both directions...
But this isn't the real problem!
In the EU, you have additional problems with packaging and e-waste.
This is done per country!
So you need to talk to waste and packaging associations in 27 different countries or pay premium to get someone to do this for you... pretty annoying.
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