Long story short, I was accessing the tunnel behind the petrol fill tube and noticed a small knob on the top of the suspension...

So I start thinking that my car might have adjustable shock absorbers. Under the car with the camera and look what I found!

I did some Googling with the numbers on the shock and it looks like I have the oh-so-popular Koni adjustable shocks on the back. Sweet!

Now I need to work out if I should adjust them. Is it as easy as turning the knobs and going for a drive to see what feels the best?