Rear shocks worn out?
 

Hello, I've a MKIV Golf, it's my second Golf (previous MKII) and it's developed a ride characteristic.

It's the rear suspension shocks I think, when I go over bumps there is a heavy thud from the rear shocks with a definite feel of the bump, do they need replacing?
If so how much would it be and what are my options?

I have heard they do gas or standard spring models. Are the gas ones that much better?

It's a W reg 2000 model with 56k on the clock. I am based in Folkestone, Kent, UK.

thanks