Did you ask Ansell if/when they will run the tests you need? If you are a high volume buyer or if Ansell is considering additional tests, you would find them very cooperative.
As for 3rd party, try competitive brands of nitrile gloves as well as nitrile manufacturers.
If it is urgent and really important, or if nothing else, do your own tests - fill the glove with the bleach and see how long it takes to leak through. If you have some $ in the budget, hire a lab to do the same test Ansell would do.
Since your company is already using the glove and the bleach together, what are your real life experiences telling you? Those are more credibile that lab tests anywhay!