Thanks Bogro,
I kept looking at that logo and knew I had seen it before but never thought of Texaco, I thought it was like one star = one point.
So it could be a possibility that you got one of these free if you spent so much on your petrol or you had to collect tokens for them. Working on that line of thought there might of been 6 or 12 to collect depending on how long the promotion ran for.
As for how I got them, well, they both came from Ebay, bought roughly a year apart.
I'm sure some Dutch collector will have all the answers and maybe even the full set of these promotional Dutch exclusive specials.