On 10.10.2011, at 03:37, Brian Ferguson wrote:

I have created a document with the Page Guides coloured 'green'.
Having forgotten how to do this, I can not get back to the Palette or whatever it was which allowed the change.

I found this in the Help, p. 375:

Customize the color of your Page Guides

1. Select Invisibles & Guides in the Customizable Colors column at the bottom of the Preferences window.

2. Select Page guides in the Invisibles & Guides column.

3. Click the Page guides color swatch and choose the color you want from the Colors panel.

Thanks for giving me the opportunity to learn something new. :-)

Þorvarður