I decided to visit the garden centre I got it from to ask about it. They had 2 more 'crimson star' clematis for sale that were blooming the exact way that mine is, with double flowers and not looking like the photo on the tag. He (the worker) just said sometimes they have different ways of presenting themselves, although he seemed surprised that what was blooming was what was in the photo too. I do think it is flowering very lovely, just not what I was expecting. And I'm still not convinced it's properly tagged. I'll be keeping an eye on it since this variety seems to lack info online.
