Alan,
Looks like you've got the wrong diaphragm. The one on the right is (probably?) an MMD3ATN8M, our all titanium dome for the DE75TN. You seem to have determined that EAW is using the DE75 (not TN). I honestly don't know whether that is correct, but Charlie probably does so I suspect he's steered you right. The only difference between the two is which diaphragm they take. Judging by the photo of the original diaphragm, and the aftermarket one on the left, you probably really want an MMD3A8M, which is our titanium dome with polymer surround (used in the DE75 among others). The two diaphragms have a slightly different character, and you want to make sure they're matched to what's in the rest of your boxes.
I don't know anything about the aftermarket diaphragms available, but I do know a thing or two about what it takes to make one of ours. I would buy the genuine item, anything made right is going to have to cost nearly as much, otherwise they're not keeping close enough tolerances or using the right grade of titanium and glues.