You won't be able to use 059 or 0161 if you have voice calling over broadband.

Only some people with traditional fixed line calling can use 059 or 0161. If you dial 059 (or 0161) before making a call from your home phone, these calls won't be included as part of your Talk plan and you'll be charged Spark retail rates. We have some of the cheapest phone rates and talk plans around so we don't recommend you use these codes.