I started hearing a more noticeable knock when going through potholes after fitting the new IC from the front left of my car. I'm sure it was there before but much more subtle. I thought it was just the VWR drop links that knock a bit on rough roads. After a bit of investigation the source of the knock was found. It was the left arm of the steering rack... The internal slack happened to my car too. Fortunately a friend had upgraded his recently to get Lane Assist working on his Golf mk5 (a Gen 3 steering rack is needed for that to work), so I asked him if he could source another from the same parts breaker. He knew they had another in good condition. After a short call it was paid and the shipping was sorted.
Two weeks ago I finally had time to go get it fitted. Another friend showed up with VCP and flashed the steering rack, that was from a Leon mk2, to have the mk6 GTI steering weight profile. He also updated the firmware version.
Calibrated the steering angle sensor and it was done. All coded with no errors.
I think the steering weight profile from the mk6 GTI is like our factory profile. I prefer it to the mk6 R that I have on my diesel mk5 (lighter steering when driving slow).
No more loud knocks (just the subtle knocks from the VWR drop links...).
Oh, and I'm waiting for new track tyres: Yokohama Advan Neova AD08R.