Nissan X-Trail - towbar connectors

jelv

We are about to order a new x-trail, but are unsure what we should aks them to install in the way of connectors. Our caravan has two 7-pin plugs. The dealer is suggesting we have a 13-pin socket fitted (ready for if we upgrade the van) with a 13 pin double socket adapter. Any drawbacks to this arrangment?

This one on Towsure looks similar.