Hi David,
You probably thought you had an outcome and here I am about to question it...
Although I don't offer a positive country of origin, I strongly believe that your pieces are not Yogya silver as suggested. Sorry Alex.
I have quite a number of pieces of Yogya silver myself and they are easily recognisable. The whole design basis of Yogya silver is that it draws on elements of nature, native to the country (now Indonesia). If you look at the reference sites supplied by Alex you will note that the designs follow patterns of plant life (primarily stylised lotus flowers) and birds (peacocks), with thin rope borders. Note also that flat areas are planished(a textured finish left by a planishing hammer). None of your pieces contain these elements.
The thing in common your pieces have with Yogya silver is the format of the marks. As you can see yours and Yogya silver all have an 800 stamp plus what appear to be initial makers marks only.
My feeling is that they may be Italian, and made prior to 1934. The marks could also fit this scenario, but without a definite country/town identifier, it is very difficult to be certain. I know there are some Italian silver experts floating about this forum who may be able to offer an insight?
Anyway, have a look at the 1872 - 1933 period in the link below and see what you think.
http://www.925-1000.com/Fitalian_marks_01.html
Cheers,
Steve