I've just gone through this. My order was within the VAT cut off, and could have had the car on a 59 reg with a delivery in mid Feb and save on the VAT.
But as I've elected for a 2010 March 1st reg I got hit by the 2.5% VAT rise.
It's swings and roundaboutes and will prob will ballance out:
59 reg = lower resale as older plate, but you shoulds save on the VAT as VW pick this up to end of Feb.
10 reg = better resale as newer plate, but you get hit on the VAT.
VAT 2.5% worked out for me about £600 due to spec of the car, the dealer advised the drop in resale due to the new plate & year would be about £700- 900 in the long run (seems year change plates such as 05 to an 06 has a bigger drop than an 05 to a 59).
Not sure what the state of play is if VW push out your build week \ etc so your delivery is an 10