Visa application details

Hi I received my working holiday visa a few months ago and booked my flight around a month later, however since then 2 things have changed.
1. My port of entry has changed on my application I left it blank as obviously I had not booked a flight without the visa however the embassy staff made me put one so I just put haneda/narita however when I was booking my flight I forgot about this and my flight is to Nagoya. Will this matter ?
2. I�fm staying with my girlfriend in Japan and I used her address as where I will be staying however she has since moved house , will this matter ?

If you already have your COE/Visa, it doesn't matter which airport you land in when arriving. At the immigration area, they will issue you a residence card if you're staying in Japan for a long time. If you have a different address as to where you're staying, you just need to make sure you include that as the address for your residence card when you arrive in Japan.

You can also go to the local city hall of where you're going to be living and update it there as well if need be, but that just seems like more work rather than just telling the immigration officers and getting your address updated right then and there.