I only bought it cause I's never seen a yellow before and I worled for Nissan for 7 months earlier this year
There is definately none here in Grimsby anyway
As a comparison this UY is advertised at West London Nissan (Shepperton) for £21489:
"2005 05 NISSAN 350Z 3.5 V6 GT4 3 Door Coupe
YELLOW, Insurance Group 19, 32400 Miles, 2 Registered Keepers, Full Franchise Service History, Franchise Approved, HPI Checked, Car Data Checked, ABS, Alarm, Alloy Wheels, Body Coloured Bumpers, ...More, Tel: 0845 8110349"
So 18k (albeit on an 04) looks a pretty good buy + like the plate you bought Even better if it is an 05 looking at your other thread about plates