The most important thing about going bankrupt NI is the same as in the UK, you have to establish COMI there, (Centre of Main Interest), meaning you live there, work there, pay tax there, pay electricity/gas there. You will have to be able to prove when you go into court that you really ARE mainly in NI and not just popping back and forth. You need to be there for the majority of 6 months, meaning 3 months and 1 day minimum, but normally nearer to 6 months to be sure. If you were still to be self employed in the south, presumably paying tax in the south also, meaning that the COMI looks shakier. Hope that helps.