plumbing; installation of plumbing; maintenance of plumbing; plumbing services; repair of plumbing; plumbing installation, maintenance and repair; installation of plumbing systems; plumbing repair advisory services; installation, maintenance and repair of water supply apparatus; maintenance and repair of heating apparatus; maintenance and repair of heating installations; shower installation and repair; water closet installation and repair; installation and repair of water closets; installation of heating, lighting and cooking apparatus; maintenance of bathtubs; repair or maintenance of gas water heaters; installation of pipes; installation and repair of toilets [water-closets]; toilet [water-closet] installation and repair; maintenance of apparatus for purifying water; installation of water pipes; installation of equipment and apparatus for gas and water supply; repair or maintenance of water purifying apparatus; emergency servicing of water supply apparatus; repair of water supply installations; repair of gas and water installations