Real Estate / Poland Notary Agreement after a purchase of a property - very expensive! [14]

My girlfriend purchased a property recently with a little of my help, although she is the sole name on the banking agreement. We have been to the solicitor in Krakow to have a notary agreement put in place outside of the bank agreement. i.e we are not married so the property will be split 50/50 .

The solicitor charged £50 for advice / getting a legally binding agreement drawn up which we / I thought that would be the cost of drafting the agreement, + a translator cost which I expected to pay when we go to sign the agreement. The notary / solictors have now told us it is £450 as this is the cost of the time to draw up the agreement e.t.c. its quite complex e.t.c ( we have a copy of the agreement which they emailed us though) This seems ridicoulously expensive,why did they not advise of this extra cost at the time of giving the advice? We havn't signed anything agreeing to this amount ? Anyone have experince of these sorts of agreements at all ? Is this common practice ? Whats your thoughts?