Depending what you are making, your product may need to be tested or examined. Trading Standards offers information on regulations in areas such as labelling of textiles, cosmetic products, and the safety of consumer goods. Talk to the British Standards Institute to find out what standards might apply. They also offer product testing. Look at competitors to see if they make claims that their products live up to certain standards, and check whether these are mandatory or just good for marketing. You may want to mark your product with the CE mark, which indicates it complies with relevant European directives, and aims to facilitate European sales.