Engineers or companies registered with Gas Safe can issue a Gas Safety Certificate. To confirm if someone is Gas Safe registered, simply ask to see their Gas Safe registration card (before work commences). This will have an unique number on it and a photo ID. Go to the Gas Safe register website and check their credentials. Type in their unique ID card number. This should bring up the engineer’s details. If you are satisfied that they are a bone fide registered engineer or company then proceed with the works. If they are not, DO NOT use them.