The Construction (Design and Management) Regulations 2015 apply to every construction project, from a full site to a single-day install. As a contractor you have to plan, manage and monitor the work under your control so it's done without risk, coordinate with the other duty-holders, and, where you're the only contractor on the job, prepare the construction phase plan. In practice that means keeping a current RAMS for each job, the crew briefed and signed on, plant in test, operatives competent, and a record that holds up afterwards.
Sitting over that is the HSE: site safety is enforced, and under RIDDOR reportable injuries and dangerous occurrences have to be recorded and notified, with records kept and readily accessible for at least three years. When a client or principal contractor audits you, or something goes wrong, the question is the same, can you show it?
The work is familiar. The friction is producing a fresh RAMS for every job, keeping tickets and plant certificates in date across crews that move daily, and pulling the evidence together when someone asks. That's the part CalmCompliance makes calm: each job carries its own current, acknowledged record, built as the work happens.