I have some office furniture visitors/guest armchairs of the slay back design an example of which can be seen at the following link:
https://newspirit.co.za/wp-content/uploads/2024/08/AF-8578.jpg
Alternatively, I can supply you with pictures by email or mobile phone of the chairs I wish to have repaired. The slay back design is notoriously weak since they are prone to bending and collapsing when a heavy person sits on them. The work that needs to be done is to bend the slay back 25mm round mild steel tube back into its original shape and then to weld an approximately 300mm long gusset fabricated from 25mm round mild steel tube to match the existing tube, at approximately 45 degrees to the horizontal member, connecting to the sub-vertical member, thus making the bend rigid which will prevent the slay back from flexing as intended by the designer. I can spend the necessary time at your workshop to discuss my proposal which will hopefully benefit from your expertise in these matters. I need to do this work at the least possible cost or purchase new chairs which is not an option.