Real Estate / Help with Poland mortgages! (not married couple) [4]

Hi all,

I am British and currently living in Poland (I have NIP, PESEL and a karta tymczasowego pobytu). My partner is Polish. We are not married but want to buy a flat together. We need to take out a mortgage to cover about 78% of the purchase and want to be co-owners (50% each). I am not currently on a permanent work contract (naturally I teach English) and the bank is asking for confirmation from the UK that I have no loans/mortgages - can they request this? What will I need to show the bank? If we were married I would simply be considered dependent on my partner - does anyone know the rules for co-habiting couples in Poland? We want to get married in a few years but want to be settled first!

Thanks