[Biggles]

Good choice to use stainless if you burn solid fuel. Our Rayburn range burns coke and anything mounted on the chimney is eventually compromised due to the mildly corrosive fumes coming from the stack. A lot of standard rigging items seem to be made from fairly soft iron too with a rather thin galvanised coating so they don't last very long when exposed to smoke. I just tend to coat mine with black underseal clag and inspect them fairly often. I'm a bit of a monkey for trying out new antennas so that isn't a problem, and it keeps the neighbours entertained when I'm clambering about on the roof. I find that a bit of plastic tubing pushed over exposed threads on bolts helps a lot when you need to remove the nuts later on.
Alan.