What part is this called?

[shokenore]

Very true, but if you believe there is play in it then it will need to come off to be replaced.
The new bushes may either fix it or make it serviceable enough to give you some time to source a new replacement.It can't make it worse.
It is only a couple of bolts to remove it.
When I removed and stripped mine I was quite horrified at the mess of the inside.
But after a clean up and new bushes it has been through several MOT's.
Happy spannering.

[KERRSURF]

It would have to have been very dry inside for quite a while to damage it, the bushes should do the trick, plenty of grease.