A: The education systems in the UK are diverging as the effects of devolution become more pronounced. Despite the fact that European Union provisions for the free movement of workers do not apply fully within nation states, suitably qualified teachers can apply for registration to teach in Scotland or Northern Ireland through the appropriate teaching councils. In Northern Ireland, the same procedure applies as in England, and the appropriate government department would need to certify your eligibility to teach. You could transfer in your induction year, but I would not recommend it unless you have a good reason to move mid-year.
Remember that Scotland and Northern Ireland are small countries that have relatively few problems with teacher supply, so jobs are not always easy to come by, even for those who train there. Without local roots or support to find a job, you might well face an uphill task. Northern Ireland has recently introduced a national supply register, and you might look into the prospects for finding temporary work. As in England, most jobs have a September start - another reason not to move at Easter.
I hate to put you off, especially if there is a good reason for your wanting to move, but where house prices are cheaper there are rarely shortages of teaching staff - precisely because the qualifications allow teachers to move about relatively easily.
If you're really determined to get out of London and the South-east, you might consider other parts of England, or maybe even consider teaching overseas for a few years. Bear in mind that it will always be more difficult if you are looking for two teaching posts together for you and your partner.