I have it and I don't think it's see through. Thinnish material but not see through. I think I could've sized down actually but couldn't be bothered with the hassle of returning in case the size down was way smaller and it turned out I needed my normal size after all IYKWIM
I tried the navy on yesterday. It wasn't see through and I didn't need to size up. It was very flattering but I didn't buy it because navy scares me a bit. I also tried one on in Mint Velvet (the last one on Ginger's link) but it was nowhere near as flattering as the Janice.
If I did buy the navy one, could it be worn with a jacket over for work, does anybody think? And if yes, what kind of jacket?