Richard ...
John .... I'm surprised with modern scanners, cnc cutters etc that someone hasn't set up making perfect copies of traditional deco windows in stainless .... Deco houses definitely need keeping up with ... the style is very clean and sculptural ... looks great while perfect but loses the effect quickly if the (usually white) walls get rust-streaked or the windows degrade.
K
When we looked to replace our art deco crittall windows with double glazed units over 13 years ago, there was only one company in the UK at the time producing double glazed crittall frame style windows using a coated aluminium frame! And it cost about 3 times more than upvc equivalents.. so cost may have a bearing on replacement. Its the same with cast iron guttering, its extremely expensive to replace these days, compared to when it was in everyday use before plastic.
Our house which was an individually architecturally designed residence of a mine owning family, also has an interesting ingredient in the lime mortar not used in other houses around us. Because of its coastal location, it had fly ash (produced from coal powered electricity generating power stations) in its lime mortar that makes it very resistant to marine environments,