Start by checking whether your activities fall within the Regulated Activities Order 2001 and whether an exclusion or exemption fits. Carrying on a regulated activity without permission is a criminal offence under the Financial Services and Markets Act 2000, punishable on indictment by up to 2 years' imprisonment, a fine or both. Applying when you do not need to locks you into ongoing supervision.
Check if your business needs FCA authorisation
The regulated-activities perimeter, exclusions and exemptions.