Complicating things, though, was that Harry was supposed to have merged with his younger self. Being identical, his older core would simply have replaced his younger one's core. His new core was an adult's core, but if he were careful, he would merely appear very magically advanced for his age. That had been his first thoughts when Death proposed this adventure.
However, now, with Death's prank, that was out the window. Instead of replacing Gilderoy's core, they had merged into one larger core, one with two centres offset from one another. What that meant he hadn't the slightest idea. On the bright side, he was probably on par with Dumbledore in power. Unfortunately, that was still less than what Voldewhore had available when he was reborn. But Voldewhore cheated — his Death Eater mark was also a power leech on his followers, artificially boosting his power to ridiculous levels. That was another reason it had taken Harry so long to flush the shite. Harry had to reduce Tom's marked followers to the point where Harry had a decent chance of beating him — although some might consider it cheating to apparate behind the other Wizard and lope his head off with a sword.
And his changed magical core meant that Gilderoy's wand no longer worked very well for Gilderoy/Harry. The wand chooses the Wizard, and the Wizard he now was wasn't the one that Gilderoy's wand had chosen. He needed a new one, and fast! Harry might be proficient in wandless magic, but as a Hogwarts' Professor, he would need a good working wand to demonstrate the spells. And while it might be fun to teach them all wandless magic, not everyone had a magic core capable of standing the strain of that style magic for extended periods. So, a new wand was in order.
But he couldn't just pop into Ollivander's. As crazy as the old man appeared, he was extremely sharp on wands and would definitely suspect something was wrong. And Harry/Gilderoy most definitely didn't want people getting suspicious of him at this stage of the game.
After the potions were finished from the damned unlively Healers at St. Mungos — the Witches had been remarkably resistant to his natural Wizard charisma, Gilderoy thought — this amalgam of Harry and Gilderoy decided to go fetch a custom-made wand.
But Gilderoy did have a point that there were some very hot mediwitches wandering around in St. Mungos. When Gilderoy began categorizing them according to their hip-to-bust ratio, and how much fun they might be in bed, or against a wall, Harry's response was an uneasy, "stop it," followed by the distraction of planning how to get the various horcruxes.
Flirting was one thing, going farther was an area Harry wasn't sure he wanted to explore just yet. He wanted to get a bit more comfortable with his new body. He might be ready for such blatant activities in, oh, say, thirty years.