As long as any claims you make about the product are true, just sell it. If you're going to connect to the mains or the National Grid to power it, make sure it's safe. If you're going to put a CE mark on it, make sure you can prove your compilance when your competitors complain to Trading Standards and make trouble for you. Sell and be damned - making sure your product liability insurance is paid up if it's likely to hurt someone or burn their business, house or car down if it malfunctions.