I just wanted to upate this post as i ended up using the above mentioned law office to obtain my confirmation of citizenship and birth certificates and just wanted to help anyone if they are in my position a few months ago.
The people who i dealt with, Piotr and Michal, are both professional and good communicators (swift replies and their English is great). I was luckily in Poland at the time of completion and could therefore pick them up personally and meet them.
I guess i had understandable worries that this may be some sort of scam (as i was dealing with people on the other side of the globe without meeting them or hearing about them) however its all legitimate.
Their prices are much better than any Australian office offering the same services and would recommend that you give them a go.