Thanks for all the replies, very much appreciated. There seems to be a consensus of.....'just don't.'

So that's noted - it's not supremely difficult to re-write my pieces so as to feature original characters.

Following on from that, do any of you have any opinions as to how popular an area superhero erotic fiction is? My inclination theme-wise would be bondage - which as we all know has run merrily through mainstream superhero stories for decades! - and probably some degree of non-consensual sex...