I am persevering with a box of Fomapan 400 without much success. All my negatives (taken with an old 127mm Ektar and tray developed) seem to lack contrast in D76 1:1 even though I've extended development times well beyond what I've found on the web.
I'm now going to try it at ISO 200, extend times even further and see what happens. I also have Ilfosol 3 and Rodinal in stock which I could try.
Does anyone have any other suggestions?