This is something which affects cars with an RRP over £40,000, irrespective of any discount. My father has an Allroad on order which was due in February, but the dealer now said the build week has slipped and it is likey an end March delivery. If the vehicle is registered on/after 1st April 2017, then there is the first year tax (which is included in the RRP), but then each car (unless electric) pays a flat rate of £140 per year (i.e. no free tax for sub 99g/km CO2 etc). The problem is with cars costing more than £40,000 RRP, there is an additional charge based in addition to the £140 dubbed as luxury car tax. This is payable for years 2 to 6, i.e an extra £340 on top of the £140 for 5 years. A pretty huge increase in RFL!
The issue my father is having is that Audi won't guarantee the car can be registered before the 1st April (he ordered end November). As the car hasn't been built yet, it is looking likely that he will cancel the order. This was never an issue he queried about at the time of ordering as he was always aiming for a Feb delivery, with possibly delaying to 1st March for a 17 plate. The dealer also don't seem to be very knowledgeable of the new rules (unless they are playing dumb to avoid highlighting it of course!).