HI, can anyone help me out on a annoying rear seat spring seat noise

. the passenger side rear seat makes a noise each time the car goes over a Bump or pot hole when someone is seated on it. It sound like a Spring noise - click, clunk type noise, Its as if one spring is loose.
Anyone had this issue and can point me to a possible fix please?
Thanks,

58 X5 E70 MSport 3.0d
my boy racer BMW cars:
1990 E30 325i Saloon with full Mtec Kit (i wish i kept it -

)
1985 E30 318i Convertible ( if only i kept it

)
1999 730i