Hi thete,
There is a Manhole Cover Exhibition at CACHe now. It is approaching its last leg of the slot, but if you are in the area it is worth a visit.
The exhibition is a small one. Anyone who had been to CACHe would know the room is not that big. But the exhibition covered from the ship-building and foundry industires, with scaled models of wooden moulds of the covers. There are also a small collection of the covers in the room.
A whole wall was dedicated to all the known foundries, both local and foreign, the decriptions of the markings, abbreviations.....
T