crittal steel bi fold doors

You could try Crittal.
https://www.crittall-windows.co.uk/home-owners/products/

 

I would have thought Crittall would have made them.
Try this company.
http://www.fabcosanctuary.com/the-steel-window-company/bespoke-design/

 

Not going to be cheap to make them.

Could try Clement, looks like they have a £5k minimum order value according to one review, which should easily be met.

There were a few steel window manufacture at the show, but not come across a bi-fold.

 

Seen this on e-bay, first time I've seen this:

http://www.ebay.co.uk/itm/Crittal-b...429198?hash=item3f7c8b148e:g:qs0AAOSw~y9ZGZFY