Ahh, gotcha. I thought Custom Search was that old thing they had which let you create a "customised" Google Search which had your colour scheme of choice and op

Ahh, gotcha. I thought Custom Search was that old thing they had which let you create a "customised" Google Search which had your colour scheme of choice and optional restriction of the results by topic (i.e. basically standard search), not the equivalent of 'site:x'.