I’m also collecting my replacement Tiguan R-Line this week. We do 6000 miles per year and like I was thinking the same. I’d only consider petrol if I was buying it personally – when leasing it’s diesel fall the way and since the AP for the Tig is so low why not? I have had diesels last 10/15 years and no problems with dpf. However, I always run them on Shell it BP so if you stick to premium fuel and do the odd run here or there you should be fine.