Here is some info on Gulf colours that I picked up from somewhere - it may even be correct! I am sure the originality pedants will know.
Powder Blue PO30-8013
"An original Production Car Record Sheet shows the Light Blue code to be (P030-8013) and the Marigold (P030-3393) both being British Leyland (Triumph) colour.
Here for the gulf colors(the originals):
Berger Ref 1125 Standard Triumph Powder blue
Berger Ref 1465 Triumph Marigold
The dark stripe between the orange and blue should be dark blue."
045 RENAULT ORANGE
051 TRIUMPH POWDER BLUE
I have also been told the following are the same
Berger paints No 1125 standard Triumph Powder Blue ICI no. 8013.
No 1456 Triumph Marigold ICI no 3393.
Powder blue (PPG 12163)
Topaz (orange) (PPG 60812)
Royal Blue for thin stripe between orange stripe and powder blue (PPG 13126)
The Pale / Powder blue PO30-8013 and Marigold PO30-3393 are not the true Gulf colours but ones of the Wiltshire Oil Company (that Gulf acquired). So all you have to do is to say your car is not in Gulf colours but Wiltshire.