WANTED: Pre potted plants

Hello new to the group Anyone selling a preformed pond in surrey 1000L+? Or does anyone sell pre potted plants? I have purchased a house with a pre formed pond thats been installed for over 30 years. I am doing a complete water change as its heavy green water with 6 inches of black silt. Its had no filter for 15 years or airation I have installed a 4000L pump and three air stones but im cleaning it daily as its full of grime. My local aquatic centre reccomeded a complete replacement of water. Pond has a hole somewhere as it drops 3 inches after filling. Looking for beneficial items for the pond of anyone has anything based in epsom. I have around 40-50 fish that are breeding following a big clean and filter insulation