XC 60 D4 or D5?

[Petetamora]

I’m considering buying an XC60, current model, probably a couple of years old. It will be replacing a Freelander 2, (which contrary to popular belief has been totally reliable), taking over daily duties and caravan towing.
I’m wondering if it’s worth the extra expense to get the D5 over the D4? Most reviews I’ve seen suggest the difference isn’t significant to bother. I’ve not driven both yet, but anyone with experience got any useful pointers please?