Vintage Set of 4 Stacking Dining Chairs

An unusual set of 4 stacking chairs.
 
They each have metal brackets and the frames are solid wood.
 
The chairs are well used and have signs of use all over them such as scuffs, graffiti and patina.
 
They appear to be from a school or college originally for multi use so perhaps used in a classroom or canteen.
 
Some of the back and seat heights vary slightly by 2cm which would be great if you have people of different heights using them.
 
1950's ca.
 
Dimensions
Back heights 79-81cm
Widths 43cm
Depths 43cm
Seat heights 43-45cm