I bought a couple of Vivitar 285HV flashes a couple of weeks ago, and one was missing the AA battery holder, so I went to eBay and ordered a five pack of them. They came in today, and I immediately tested them out with my NiMH rechargeable batteries. Unfortunately, it was way too tight to slip back into the flash unit once the batteries were in place. I had the same problem with Energizer rechargeables too. I was afraid to push the holder in all the way in fear that I would have to use needle nose pliers to get it out. Generic CVS alkaline batteries worked just fine - they would slip in and out with no problem.
I noticed a little screw on the end of the holder that held a butterfly support in place. Once I unscrewed it, and removed the support all the batteries went in smoothly, and would fall right out without having to use pliers.
They also did not have any indication as to which side was positive, and which was negative, but I have one original holder and was able to figure it out. I marked it with a silver sharpie so I didn't have to think about it.
Anyway, I have two extra that I will be posting soon if anyone needs them.