I carefully checked through Bennett's "Collecting Irish Silver" which is the most appropriate reference I have on the subject. I also checked through the regular references such as Tardy's International Hallmarks and the abridged version of Jacksons' Hallmarks.
Here is view of the piece from the top.

Here is the underside of the piece. The hallmarks are in the centre of the piece.
Here are all the hallmarks. As one can see, there certainly are a large amount of them.

I have made enlargements of some of the more difficult groups:


I felt like this could be the maker's mark and I present it rotated for easier analysis.

I am looking for assistance with this piece. If perhaps the "D" mark (far left) does allude to a year. I have been unable to find this style of harp. Nor anything else.
I also did a search of the .925 resources.
I hope you will be able to assist me. I'm very interested to know more about this piece.