Hi guys, I really appreciate your support and how quickly you have replied. The issue is now sorted, thank you!! So I arrived in Canalave, went to the Poke Centre, then checked out the guy who takes you to the Halloween Event. I battled 3 people I believe then came back, visited the Poke Centre and crossed the bridge (no Barry). I battled the gym, Barry was waiting outside where he spoke to visit the Library. I wanted to heal first so as I crossed the bridge for the PokeCentre he battled me and (as I was so weak), he won. He then healed me after the battle and I visited the library.
If there is any way that I can review how well you guys have helped me, please send that my way! I didn't get all the way to Sinnoh for it to bug out now haha! Thanks again and enjoy your day.