Don't give the "Psylocke can use telepathy so she auto wins" crap. There are a multitude of spells that Potter can use on himself that could negate her powers. Two such examples are the impervious charm, which would allow him to fight off her telekinesis by negating it's affects, and the disillusionment charm which would turn him invisible. Can Psylocke use her psychic powers on those she can't see?
You obviously don't understand how potent of a mutation Telepathy truly is. Name any faction in Marvel, the X-Men, Hellfire Club, S.H.I.E.L.D, HAMMER, The Brotherhood, name the faction, and they have fought and killed over mutants like Psylocke that possess Telepathy. Know why, because it allows you to have that auto win crap. Know what mutants like Psylocke, Emma Frost, Jean Grey, and Professor X all have in common despite being mutant telepaths? They are able to shut down and destroy the minds of anyone from just about anywhere.
He could also use the gemino curse on himself to create multiple clones of his body which would provide a distraction long enough for him to use something serious. Based on what I've seen with her speed she's not fast enough to dodge one of his spell as point blank range.
Psylocke has been able to tell apart Jamie Madrox from the vast amount of his dupes, just by reading the mind of one of them. Jamie's dupes are truly living people under the control of Madrox Prime. I don't see how Psylocke can't tell apart the really Harry in a matter of seconds. Also, if Psylocke and Harry were in point blank range she has the martial arts ability to take out Harry with one simple blow. She's a bloody ninja, before Harry could even chant a spell his wand would be sliced in half by Psylocke's katana.
He's used both the cruciatus and the imperious curses before, so there's no evidence that he wouldn't use them against her. The former would cause her so much pain that's she's likely to pass out, while the latter would allow him to take control of her mind. He could negate her telekinesis, and then put her to sleep for an easy win.
I doubt Harry, who people have stated time and time again, was horrible at keeping out telepaths from his head would be able to intrude into the mind of a powerful telepath and take control? I hate to bring up this argument again, but Betsy can attack physically and telepathically. I doubt Harry would be able to defend himself from one attack or the other, let alone at the same time.