Just had the front Upper control arms and ball joints changed due to a knocking noise coming from the front of the car.

Although it was easy to see that the rubber bushes were cracked the rest of the suspension components looked OK, with no splits in the rubber bushes or other obvious faults.

The next day, I was surprised to still be able to hear a slight knocking, albeit just noticeable. I don't want to end up changing everything under there, so what could I do to check the condition of the rest of the components to rule out the ones that are OK?

is it when you go over bumps, up kerbs etc?

I had a noise that ended up being the drop links. Got - 2017 SDV8 Autobiography in Loire Blue
Had- 2008 TDV8 Vogue SE in Java black
Had - 2007 S/C in Stornoway Grey

It is a faint knocking sound when going over an uneven road.

Could still be your issue in that case Got - 2017 SDV8 Autobiography in Loire Blue
Had- 2008 TDV8 Vogue SE in Java black
Had - 2007 S/C in Stornoway Grey