Law / Registering in Poland for a NIP tax number? [9]

Hi just a quick question,
So I have recently moved to Poznan and found a bit of work (very small, one day a week).
Anyway my employers told me that I need a NIP tax number.
I started looking into registering today and found out what I need to do. I went to the citizens and foreign department (or something like that) and I have to fill out a form and send it with a copy of my passport and job contract, wait 2 weeks for the reply then take that to another place to register a temporary stay of more than 3 months.

So I have a few questions.
Is all this necessary for a few hours work?
What does registering in another country do to my situation in my home country (Ireland)? When I go back do I have to register in Ireland?

Any help much appreciated.

Law / Getting loan, overdraft or credit card in Poland [8]

Hi everyone, I'm wondering if anyone has any advice on getting either a loan, overdraft or credit card in Poland?
I've been registered here for 2.5 years, I have a one person company so I have an address as well as PESEL, NIP, REGON.
I have a bank account with a yearly salary between 50 and 60,000pln but my bank refused a credit card with a limit of 5000 and and recently an overdraft of 2000.

Even though they told me 100% for the credit card at the last minute they had to refuse because I don't have a Polish ID.

Anyone have any ideas?