Otto Wagner designed bentwood chairs for Thonet around the turn of the century. Take a look at the Chaplins website and the list of designers they represent. If you link to Otto Wagner you will see his chairs that are in current production. Our reader replied: Perfect! I had a look at Chaplins  (what a treasure trove) and found they had many Thonet chairs. Although they don’t seem to have the exact same design, even on the Thonet website, they do stock very similar ones which might well do the job. Thank you for your assistance and congratulations on a great website!