Would it be possible to get the Sonoff & Slampher CE (RF/EMC/Security) approved?
As it is, they look would comply because of their serious construction, but a certification is required if you want to sell them in Europe.
People would pay a premium price for this approved devices.
These elctrical items need approval to be sold and installed in the EU. If you don't supply appropriate certification, selling these products will be breaking the law and subject to fines of £5,000 in the UK for instance. Furthermore, if these items are involved in any electrical fire, they will void the insurance policy covering the property in which they are installed.
Simple fact is, you are required to obtain certification and if you can't afford to do this, then raise the capital or have a EU qualified engineer who is qualified to carry out the tests do so on your behalf under self certification. The consequences of failure to do so could end up in all your products sold in the EU without certification being seized in storage or as they arrive in customs.
If you want to actually grow your business, get scertified or die