Thanks Husse ! I had a look in there as you suggested .. everything seemed to be normal, except nothing wanted to play ...
Anyway I had a fiddle about with a few settings, both in here and in the mixer (double-clicking on the speaker icon) and for some unknown reason things started working !!
Playing with exaile now btw ... start-up/shut-down sounds now working, at least they are in gnome. If I re-boot and go Enlightenment E17 ... no start-up sound ! I suppose that might be expected thinking about it now (different desktop manager etc)
Anyhow .. thanks for the help !!