Took a punt on a carver water heater on eBay ,gas and mains ,sold as complete,(vent cover,manual, polystyrene jacket etc) full working order but no tank it started leaking.£30 buy it now,arrived today spotless heat exchanger,appears new hose fittings,burner box corrosion free,all tested working fine ...and I have 2 spare tanks long and short...well pleased got another spare or £150 ISH profit 