if we are selling "as it is" and knocking down the price potentially someone would take it on board as a project like they would here in the UK
You sound pretty desperate and stressed at the same time. Property business in Poland is not like the UK.
If I was buying property like yours I would have made an offer. If you are Polish, get back here and try to look for a buyer- it is possible someone might buy it but be aware that the price will be very low.
On the negative side- if the plot "dzialka" is not numbered, there might be previous issues and that might scare away potential buyers. You also need to take into consideration that when legalizing the sale of that property the plot number is very important. If the buyer is getting a mortgage then the banks require the number as well.
Do the other plots near yours have numbers- if by any chance you know some of the neighbours.
In the end, you will need to get back invest some time and money to sort it out and hopefully sell it.
I know it's quite painful but that might be the best way of solving it. Considering there won't be any previous issues, theoratically it is not a difficult process. You will just have to wait for the normal processing time.