Sorry, been out all day, have to admit Mr A was not on my radar. Saying that, he has been working for a long time now and he is both varied and prolific. Intriguing!
As for how the spots are made Sue not sure what else they could be other than bits of cane - murrine I suppose, dark purple centres with lilac outer layer. Looks like some sky blue enamel thrown in and a layer of white powder including some bigger white chunks over the top.