Proof of residency
If you are exchanging a licence other than a licence issued in Great Britain, or you have previously been resident outside Northern Ireland and wish to apply for a provisional licence, you must provide DVA with appropriate proof of residency.
Documents accepted by DVA as proof that you are resident in Northern Ireland are listed below. At least one of these documents is required:
utility bill - for example, gas, electricity, telephone (not mobile)
bank or building society statement (not credit card statement)
Please note - your document must be an original copy, not a photocopy.
Your document must be dated within the last three months, immediately preceding the date of your application for an exchange or provisional driving licence. The document supplied must also be in your name and show your Northern Ireland address.
Providing proof of identity | nidirect
hope this helps, it's all beaurocratic nonsense, and if it seems too hard, why not call the DVLA? Generally they have been helpful to me in the past.