So the "stripes" on his left shoulder are uniform service ribbons -- colloquially called "fruit salad" in today's military. Here's a clearer picture of a well decorated soldier. They're meant to stand in for a medal (decoration) in situations where the medal itself isn't worn -- they are generally speaking made to mimic the top part of the ribbon a medal is hung from. Unfortunately I can't tell what decorations might be there.

Regarding the chest stars: Moore was a Knight Grand Cross of the Order of the Bath, Knight Grand Cross of the Royal Victorian Order and Companion of the Order of St Michael and St George. Those orders would have associated decorations to be worn in the form of badges or medals. The top one he's wearing looks like the Bath medal and the bottom the Royal Victorian Order medal; he may not at the time of this painting have been awarded the St. Michael decoration.

The medals are knight´s orders, the bottom one is a Victorian Knight Grand Cross (or Grand Cross Victorian Order) and the top one a Knight´s Grand Cross of the Order of Bath.

The ribbon bars are service ribbons. They serve instead of medals, so they represent awards given to him for participating in campaigns, battles, etc. It´s kind of hard to identify which ones he is wearing but if I´m not wrong then two of them should be the ones corresponding to his two Order stars.

http://collections.rmg.co.uk/collections/objects/14341.html has a little information about the painting, mainly that it´s from 1913 when he seems to have been Commander in Chief in Portsmouth. It also says he is wearing the stars of "G.C.B. and G.C.V.O.".

https://www.thegazette.co.uk/ mentions his promotions in the various orders (apart from the Victorian and the Bath, he was also Companion of the Order of St Michael and St George)

edit: some grammar and added additional information