Being an NH Reg, was it originally a VAG UK car at Milton Keynes, before being sold on at that dealer? Your Service Book will have the supplying Dealer's stamp on the first page. I would be very surprised if it is not VAG UK, being PNH, it is an early V8, as other VAG UK V8s were G+++ RNH.
If it is originally VAG UK, the good news is that DMB have them available.
Some RNH V8s in this thread.
http://www.classic-audi.co.uk/forum/...ght=definitive
P.S. Very nice car.