Perhaps these “deserters” weren’t waiting for the war to come to Ireland. Your hypothetical isn’t very compelling, BTW- why? So the RN could use (and pay the Irish government rent for) the Atlantic ports? Not exactly loot, plunder and eradication is it?
I'll ask you again then, what's the view of your nations military on Desertion?
And my view isn't compelling? Lets think that one through can we?
1. If the UK invades, then the Irish Army is going to fight however unsuccessful that would be, so Irish military personnel are going to die.
2. If the UK invades, Irish civilians are going to die (both from resisting an invasion and perhaps due to British retaliation which had occurred in the living history of those civilians).
3. Does an invading UK just let the Irish Government (which they weren't exactly fond of, see Dev and Churchill's relationship) just continue on even if said Government is hostile after you know being invaded, or does the UK exert force in that regard as well, as argued by the Unionists of NI.
4. If the UK takes the ports, then Ireland becomes a legitimate target for attack by Germany, given that the UK failed to adequately defend Belfast during the first bombing raids there, the assumption that an invasion force would provide adequate defences for Ireland outside of their own needs, seems unlikely (and remember Cork the second city of Ireland is just a few minutes flying from Cobh).
5. I would highly doubt that a UK that felt the need to invade and occupy areas of Ireland would feel any obligation to pay anything either during or after the war in regards to using Irish Ports (they didn't when they held they from memory post '22).
6. I would also highly doubt that if after an invasion and usage of them during WW2, that in 1945 the UK would have just said "cheers lads, we're out of here", which again might be a small issue for Ireland, and even if they did the Anglo-Irish relationship would be beyond toxic for at least another generation.
I find it a bit difficult to assume given how bad the living history of Anglo-Irish relations were in the period that an invasion is going to end well.