Diamond Gas replaced our old boiler with a new Vaillant in a single day. Spotless work, clearly explained, and cheaper than two other quotes. Genuinely faultless.

Boiler died on a Sunday with a newborn in the house. They came out same day, diagnosed it and had us back up and running within hours. Absolute lifesavers.

As a landlord with 9 properties I need reliable engineers. Gas certs are always done on time and their reporting is brilliant. My go-to team in London.