Steering column thunk

[Themoog]

Recently I've been working on a farm and to get to site I have to drive down a rough track. I've noticed a slight knocking somewhere in the steering column or rack so I have a few questions..
The green bushes at the bottom of the column where it exits the bulkhead - are they easy to replace or known to wear out?
The universal steering joint may be past it but I've heard of there being 2 different connections, one hexagonal and something else depending on year (mine is an 01).Is this correct?
As for the steering rack itself, can the play in the rack be adjusted if you know what I mean. I had a Porsche 944 years ago and and that had a screw that put more pressure via a nylon bearing on the rack to take out any play.
It may just be the UJ worn out and everything else fine but just wondering.
Thanks