The Regulatory Enforcement and Sanctions Act 2008 is a framework law. It is mainly about how regulatory enforcement is organised and carried out, rather than a single code telling every business how to trade.
The parts most likely to matter to ordinary businesses are the primary authority regime in Part 2 and the civil sanctions regime in Part 3. Those parts can affect how regulators give advice, plan inspections, take enforcement action and use alternatives to prosecution.
The Act also includes provisions on guidance, disclosure of information, publication of enforcement action, review, suspension and compliance with regulatory principles. That means a business can be affected not just by the underlying rule it is said to have breached, but by the route the regulator uses to deal with the issue.