We've started looking at the original presentation files about the design of Didcot Power Station. From these it seems that Gibberd's main concern was how to minimise the impact of the towers on the surrounding countryside. He considered the towers themselves to be simple, functional objects and was more concerned about their height, arrangement, and how many there would be. Most power stations have a cluster of 8 cooling towers, but Didcot A is unusual in having just 6.
This drawing shows a more conventional layout.
And this separates the towers into two groupings of four.
Gibberd wanted to create a space between the towers to reduce their impact on the landscape. This required much more infrastructure as water had to be channelled to two locations on the site.
This is the final layout.
The groupings of three are more visually pleasing.