Rainbow, I really like this. Thanks for the credit, but all I did was ramble at you a bit
As far as the Northern Irish/Irish part goes I reckon that's a more likely timeline than the canon one. If however a GM wants an Irish Civil war (another one!) You can use the idea of Free Derry as a catalyst for it. With Free Derry being established more extreme loyallists, who have been marginalised prior to this, could gain support and push for an Op Motorman 2 to reclaim the No Go areas. This could bring the Irish Army in to defend the Catholic/Nationalist/Republican controlled areas. Not the way I'd go, as due to population movement there aren't likely to be many Loyallists left in republican areas in need of "Liberation" and I reckon the struggle for survival will out weigh any local political concerns.