I prefer to sprinkle it on the compost heap where it "disappears" nicely. Aparently the potash in wood ash is leachable by rain so some of its goodness is lost when spread on soil in winter months.
Charles, in the past you have said wood ash spread in the winter tends to leach away with the rain so put it in the compost heap.
So I am surprised you have put it onto your manure mulch this month.
You are right Dalesman, I should have kept it to spread in spring. I was given a large bag by a friend and my compost heap already has enough from my wood burner.