Well my experience was a little different - I had a creaking noise which i guess is different to a squeak - it's subjective... There was no knocking at all, but the car handled like a pig.
in any case, i replaced my upper wishbones, thinking that was the cause. I bought TRW's and didn't grease the bushes. I also replaced the drop links whilst I was there.
Although replacing the wishbones sorted the handling, the noise remained.
So I disconnected the drop links and tied them to the lower wishbones and went for a gentle drive - noise gone. It was the ARB bushes.
So, in the end, I replaced the ARB bar which fixed the squeak/creak.. at the same time I did the lowers too.
Although in most cases, squeaks are due to dodgy uppers, on the odd occasion, it can be the ARB.
I should also add, I've driven about 40,000kms on the new suspension, much of it on dirt roads (unfortunately) and they are still perfectly silent.... I also live in an area with huge rainfall.. it seems that in my case, not greasing the bushes has made no difference. Touch wood!