The GTN you drove is now based in Windsor with a collector..
As for a two tone.. there is a Blue and Silver one at Richard Thorne's it's a Series 1 however it has an interim style bolt on wheels.
As for other GTN's there is one that is with a semi-dealer who tends to trade his cars on very frequently. He's had it nearly a year so may be on the market in the next 12-18 months.
Other than that... Allon White has 2 early cars (silver and green) and Brands Hatch Morgans have two later examples... 2003 again with the later interim wheels and another darker green 2002 example.
There is probably 3 people on here who are waiting for S1's to come up... although you are the only one I know of who is after a two tone.