If you look at the Dailogy, there are 2 kinds of sparkplug, one is Renault brand and one is NGK-R which I think both works fine, as long as the sparkplug gap are correct. I saw both from the dealer. I selected NGK-R and it seems they work fine.
I so not agree to change the plug every 72k. That is a lot. You should check your sparkplug every 9 months I guess, to make sure the plug are in good condition. Problem can tell from plug sometimes.