Hi Graham.
I have one of those transparent plugs. It came on a table lamp that I bought from Sainsbury's.
The flex is transparent too, and so is the inline switch.
Also, the flex doesn't have coloured cores, either, which I suppose doesn't matter too much as it's just a simple lamp.
It's a strange feeling, actually being able to see all those metal parts and the fuse, knowing that they are all live