How does one tighten these up (or even change them )
Was under the car and noticed they have some movement ( might be supposed to move a bit I don't know) but thought I'd check the bolts are tight anyway
Looked up into them and there's a round cover type thing. Nothing to put a socket on - do I have to get that off to see a bolt head?

Think bump stops are just push fit.

Yeah, I also believe they are simply push-on.