Defo bushes related. I've seen this car on my drive before. It had a Delphi wishbone on one side, with APALLINGLY soft bushes. I guess that's been replaced by a cheapo one, so still not a matching pair either way.
I'd start with a matching pair of Lemforders. If you wanted to add polly bushes too them before fitting that works well. Or get the use put of the original Lemforder bushes first and fit polly later that works too.
Track rods are not so critical to match as a pair, so I'd just change the iffy one. But if your feeling flush fire away and do both as the history isn't known I guess?
Roll bar bushes are not likely related to your issue, but will do no harm.
Delphi track rod ends are ok from any factor.
All German for Lemforder anything.
eBay for polly bushes, there a link on here somewhere.
But, given your set up guys seem to have lead you astray a little, I'd be having a bloody good check over for other faults first, before set up at wim.
As I recall the rear donuts are fubar as well. But check first.
And as said, always change suspension and steering parts in pairs. ALWAYS.
