GUEST adavis,
"...I've heard British chilluns say "a tissue, a tissue," but that's likely to be very modern..." Why so? "a-tissue" is supposed to be sneezing, why do you assume that that is more modern than "ashes"? also Reference is made to "Here we go round the mulberry bush", although this is a children's song/dance/game, IIRC this refers to the planting of mulberry trees in the exercise yards of British prisons.
Walrus