Rough hewn south facing soil bank

You didn't say what area your bank is - could make all the difference to any advice you get! It does appear to be classified as a nuisance weed in the US, but that may not apply to Ireland of course. Also as its a rambler have you checked how long it flowers for? As well as rooting from the briars it also grows from its seeds. It doesn 't sound like something you could easily change your mind about later.

As usual, a photo of the area would help, plus some dimensions for the bank itself.
Things to think about are do you view the bank from the house/main garden? Do you want year-round interest or just summer roses? Do you want ground cover roses as a low-maintenance solution or is the bank too high/steep for any maintenance.
You say you're in a rural setting, does that mean you have an informal garden?
New areas like this always seem to throw up more questions, I'm afraid, rather than a simple yes or no answer!

Just read your profile Taurman - sounds like a fantastic
location. Personally, I'd forget the privet! I've not knowingly seen griselinia but it would seem to be the more readily available evergreen hedge (if you really can't live without an evergreen hedge) but a mixed hedge would be my choice with some berries for wildlife.

I heard that the Cork area can be fairly mild. With a south facing slope and good drainage you could plant some interesting plants such as Cordylines, Agave Americana, Phormiums etc etc.

I'd second foretting the privet, it take all the goodness out of the soil and there's very little will grow under it. What height wil you want your hedge to be and will it need to be evergreen? (Sorry this isn['t what you were actually asking about) Griselinia has large leaves so would really need trimming with secateurs - a fag if its a long one.
More suggestions when you are ready to decide on that one!