Q.An existing KIWI fruit plant
We have in our garden a Kiwi fruit plant which I believe to have been growing healthily for about 7 yrs but has never produced either flowers or fruit. I presume it is a male plant?
What self fertilizing KIWI plant should I purchase and plant near to it in order that both plants produce flower & fruits?

This could be a difference in microclimates between the location of the two wisterias. One might be exposed to slightly more sun or warmth earlier in the spring, causing it to leaf out earlier. The other wisteria would then be behind its schedule for the etire season. I don't think this would be harmful, though. Here are some other reasons the other wisteria may produce its leaves late:
https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-no-leaves.htm