The Republicans wouldn't touch Scotland, they get a lot of funding from here. The Loyalists probably wouldn't touch Scotland but a paramilitary during the troubles planned to set off bombs in catholic areas in Glasgow. They hid the bomb in an oven at an Orange Lodge but fortunately someone accidentaly turned it on. With the bomb inside.
Not without Northern Ireland going into extreme violence (Think Gordon Banks). There's no real nationalist cause outside of a foreign export and Catholics are outnumbered around 6/1. Thus it makes less sense.