Law / Buying and legally using second hand car in Poland; I'm EU citizen [27]

Hello, I'm new to this site and i just wondered if somebody could help? I have read lots of threads on this topic and there are lots of valuble information but unfortunatly everybodys circumstances are different.. I am travelling from the UK to the Netherlands to purchase a vehicle then driving it to Nowy targ with my Girlfriend who is Polish, now living in England ..we are building a holiday home, i understand that the vehicle needs registering within one month.

The question is..as im at present still constructing the house would this class as an address to register the vehicle?
Do you think it may be easier for my girlfriend to register? if this is the case would she have to fill all the ownership documents in the Netherlands?

Many thanks

Law / Buying and legally using second hand car in Poland; I'm EU citizen [27]

It does have an address but as yet no sign off certificate for completion of the building. my plan was to drive it from the Netherlands, put it in a garage and wait till i return in february when i will have more time to register it, does this sound feseable?

Thanks