Hello Andy,
I've replied to you by email with an amended version of your file. I see that you had used Count mode for the X-axis so I assume you want the same for Y. There isn't a built-in count mode for the Y-axis, but we can create one by taking the Y size of the array, deducting the size of the top and bottom rows, and then dividing the results by your count number. If we take that result and wire it to the Y Size of the default, start and end segments we get a Count mode on Y.
Hope that helps,
Paul