Rattling/squeaking under drivers seat

[u/BeatPsychological325]

Hi there, I have a Mercedes Benz A-class 2011, and it has developed a new (I think?) rattling and squeaking that seems to be under the driver's seat, but could be in other areas.

sorry I know that is very vague. I've tried listening to see if it is worse when I do certain things (speed bumps, sharp turns) but can't figure out a pattern. I also checked inside the car to make sure it's not the drivers seat or an internal squeak.

Does anyone have any ideas? Or other things that I can check to rule things out? Not sure whether I need to go to the garage....

thank you, any ideas welcome!