Rear Suspension Creaking

[Guest smetz5]

Hi, I've got a Citroen C8 and after coming out of the garage from having a new turbo and exhaust fitted I noticed that when I went over bumps I could hear a knocking sound coming from the back on the drivers side. I took it back as I thought the exhaust was loose and knocking but the guy said it was fine and that maybe it was the the spare wheel mount and that he would order me some more cable etc etc. Anyway since then and still driving it around as I thought it was the the mount the knocking has got worse and now its a horrible creaking noise. I had 7 people in my car the other day and the noise was terrible, going over bumps was the worst but sometimes driving it creaks and feels like under my feet is vibrating but this only happens with a full load. Usually its just me driving so I dont hear it as much only speed bumps or coming off a curb when parked. I have taken the two rear seats out to lessen the load but I need to get this sorted. Does anyone know what is wrong? Im assuming its my suspension but any ideas what exactly? and is this something that can be fixed by my other half? any help would be so helpfull, thankyou.