So the contact settings within your handset dont have any options to show them in a certain format, I know most phones I've had can change how displayed either surname or first name 1st as such & I mean specific to remote contact list options not handset display as you've already said handset is fine, maybe check any BT settings, check any even unrelated contact settings as I atm dont recall any specific contact setup options for the BT unit & rns, however I have to go check mine shortly so I'll have a nosey, but sure its not the car as mine shows 1st/last & I havnt changed anything.