installation, maintenance and repair of gas, electricity and water supply apparatus; installation and repair of bathroom heating devices; maintenance of plumbing; plumbing installation advisory services; advisory services relating to the maintenance of plumbing; plumbing; installation of water pipes; routine servicing of heating apparatus; plumbing and glazing services; repair of plumbing; plumbing maintenance advisory services; maintenance of apparatus for purifying water; installation, maintenance and repair of water supply apparatus; installation of plumbing; installation of equipment and apparatus for gas and water supply; repair of water supply apparatus; plumbing installation, maintenance and repair; plumbing repair advisory services; advisory services relating to the installation of plumbing; maintenance of water purifying apparatus; advisory services relating to the repair of plumbing; installation of plumbing systems; installation of water supply apparatus; repair or maintenance of water purifying apparatus; plumbing services; routine servicing of ventilating apparatus; emergency servicing of water supply apparatus; repair of apparatus for purifying water