A lovely find on the street...

I found this pair of oak chairs on the side of the road today. Covered in grey mould and dust. Surprisingly they were both in very good sturdy condition. All their joints are tight, even after all this time. The seats were upholstered in a good quality tanned leather ( I kept a bit to try and match, when I re-upholster them ). The workmanship excellent. The seat panel insert is numbered to match the individual chairs. The seat stuffing reminded me of compressed horse blanket/wood fibre (not sure). The chair back is unusual. I've not seen one like it before, and my neighbour (82 years young) commented that it was different and had never seen a back like this before..... What do you think? age? maker? origin? suggestions please. Thanks for looking...