Quote Originally Posted by Kyle View Post
...I'm still new to lightroom but I assume there should be a function somewhere to pick a colour from a shot to use as a basis for other photos?...
If the shots were taken at pretty much the same time/in the same lighting, you can correct the WB to your satisfaction in one of them. Then you can either manually apply the same WB settings to the others or use the synchronize function (my preference) to copy the settings to the others. When using the synch function a popup appears and allows you to choose which settings are copied to the other files. You can choose just the WB settings if so desired.

I guess you could also save the settings as a preset and apply the preset to the other photos. But that is most useful for situations that are likely to be repeated. Like shooting indoors under lighting conditions that are likely to be the same in the future when you may want to apply the same preset.