The problem is that ITV don't build fighters up very well. You can't just say "Right, you've never seen these guys fight before but, believe us, this is a big fight" to casual fans. I'd guess scheduling it after the X-Factor or whatever would be a good idea as long at it doesn't clash with MOTD.
It's true that they aren't built up but prizefighter basically says here are quite a few unknowns to hardcore fans let alone mainstream fans YET people will watch.