Sorry to hear about the white rot , Tim. but I wonder if white rot clears itself up.
Quite a few weeks ago, I started picking my onions and noticed that a lot appeared to have white rot, which I dug up and discarded in a pile near the compost. I left the rest in the ground and hoped for the best. This weekend I went to pick the remaining onions and only 2 or 3 had the white rot out of 100 or more - previously 1 in 3 had the rot. So does the rot clear up - assuming the rot is only on the skin surface. And if we see mould on the skin surface of anything do we assume it is the end of the plant.
Also, some of the previously discarded onions with the rot, didn't have any when I last looked, and looked perfectly edible. Was this really white rot or some other mould on the skin surface.
Don't give up Tim, keep going, you will win in the end.
Regards Lily