Author's note: So I am assuming based on the fact that Harry Potter was set in the 90s that he was actually a little bit older than Buffy and all of the scoobies would probably be about two years younger than Harry, so if he is 21 than they are probably 19 or 20 (in Riley's case 21) so that would be the fifth season.
Harry had been surprised to discover not only did he have an uncle, but that that uncle was in fact alive. At first he had been afraid, the only family Harry had ever known were The Dursley's and they had not exactly been loving. But based on what the butler said Rupert Potter had lost his family in order to protect Harry, and had even left his brother in order to further protect the boy. He and Ginny had searched tirelessly for months in their new home for any scraps of information on the man. They had discovered the chest finally, and in the chest had been a few articles that the young Rupert had published, papers about demons and slayers, papers published by some group called The Watchers Council.
After contacting this Council and discovering exactly where the man was stationed a place called Sunnydale, California. The newlyweds decided to travel to this Southern California town in order to meet Harry's last surviving family member.
Giles had sat and listened to The Council try and make Buffy do all of these different tests, he had even answered the questions diligently and honestly. He had thought it funny when they mentioned Willow and Tara "only" being level five on their OWLs, he didn't think it right to tell them the two were self taught and were probably even more powerful than Dumbledore himself had been, well at least Willow. When they had finally left he was excited to be making money again. A ring of the bell told the group customers had not been affected by the rudeness of The British. A twentyish looking boy with a red headed girl walked in.
"Hello! Welcome to The Magic Box is there anything I can help you with?" Anya asked thinking the boy looked somewhat familiar.
"Why yes, we are looking for Rupert Giles they said he worked here." The boy had a British accent, and Giles could see the wand barely visible in his coat pocket.
Anya smiled "Not more Brits! Giles some more Watchers are here to see you!" Giles had a feeling he knew exactly who this boy was, he looked a lot like James.