Is that saddle kept in the corner of the shed where there's less air movement?
Interesting question. It's right at the back of the shed. I don't know whether there's more or less air movement back there. There's 'ventilation' all around the shed, by virtue of the corrugation of the walls, and the slatted nature of the floor.
In situ, this saddle is about 2 feet (maybe 2 and a half) behind its slightly higher brother, which is likewise from the eldest.
This saddle came to me 9 years ago on another bike. It is stamped as a Brooks Pro on the wings, but the metal plate on the back is small, flat and worn completely blank. I think it might be 25 years old (more or less). Most of my others are no more than 10 years old.
They are all regularly (if not often) proofed.