Just an update on the above post, took the Alphard on a long camping journey and found that the cruise control was working. Few points to note for anyone else considering the upgrade.
Green light on dash doesn't work "CRUISE" symbol to show if ON or OFF
When using you have to first hold the On/Off button in for a few seconds to turn it On
When using the stalk also have to hold for a few seconds before any response
Works below 40MPH which was a surprise considering some other posts I have read
Good upgrade once you get to know how it works correctly 😁