We also work with estate agents like savills so give yourself peace of mind before you put down that deposit! Flashshield is to be installed only by a licensed plumber/hvac installer that has successfully completed the gastite/flashshield certification test. Questions? comments? suggestions? issues? Eglow is ce marked and carries a year guarantee. A plunger and and bit of arm action! Baxi potterton myson provides a number of trade resources for installers, contractors, specifiers.