passport colours

[Gypsycobdaisy]

My welsh sec a has a welsh pony and cob society passport, she was born 08, it has all her bloodlines in it and the papers are blue. I have just been given the pony we have on loan and his passport is again from the welsh pony society, reg sec a - but his papers are yellow?? he was born 2000. My little cob is registered with a chaps passport which is again blue. My TB mare has a duplicate pet id one which is incorrect (just waiting for her weatherbys one) which is white and has no breeding info.
What do the colours mean?

 

[keep the faith]

Im assuming the colour differs depending on the year of birth? My horse is registered with wetherbys in the non thoroughbred studbook, her passport is purple, my friends horse a year younger same studbook has a blue passport.

 

[Nes]

I think with welshies mares have blue and geldings are yellow not sure if stallions are a different colur again tho