Thanks Leon, Warsaw Poland is a long way to go for an Interview and could get costly for three people, would I be required at that interview also?
You would not have to appear for an interview and interviews are not that common if you properly prove your relationship to be genuine. The processing time is usually much shorter with outland but of course it is up to you.
If an inland requires an interview, it can easily add 1-3 years to your processing time depending on how busy your local office is.