They've likely had chilling effects, haven't they? Just as with any censorship, there are chilling effects. According to some data I saw a while ago given in parliament, around 20 people a year are prosecuted for possession or production of the material, at least in magistrate courts. Taking the concerns of the graphic novel artists in a more general sense, they were completely right on warning about the juridification of the imagination. It's extremely unsettling how in the face of this you can say that their concerns haven't materialised, even given how overseas artists have lost the UK audience too. If Google were declared illegal to use, would you claim that its illegalisation has had no effect on web search?
As a side note, although there were no graphic novelists to speak for me, other regulation on fiction in the UK has had its own effects on my own online activity. The only way you'd know is if you had a keen enough eye to spot my activity cease when I was made aware of the hideous laws in England.
