I found some nice examples
But, alas, I could not find any examples of a prebend followed by a bend up.
Whats strange is that in the second example there a prebend (two half steps), then a slight dip (to one half step), then back up again. So clearly the game can go from a bent state to a higher bent state, but just not in certain circumstances I presume.
I may test in the near future. Or I may read Berneer's guide again, he was pretty thorough and may well have examined this while compliing his guide/tutorial.
For now I'll need to leave it. Pretty annoying as it's quite a nice part of the guitar solo