In the survival area buck's grandfather's place is the only place that you can battle them and the people you have paired up with like Riley Cheryl ect that's the only place I'm afraid or you could restart your game ^^
First you have to battle the snowpoint gym leader
The fifth gym leader in Pokemon platinum is crasher wake but you get the fourth badge.
In Pokémon Platinum, you can obtain the TM for Drill Peck by defeating the Gym Leader in the Veilstone City Gym, Maylene. After defeating her, you'll receive the TM60, which contains Drill Peck. Additionally, you can also find TM60 in the battle area after completing the Elite Four, specifically in the Battle Frontier's Battle Hall.
The easiest way is to use a ground-type Pokemon that knows ground-type moves. If you cannot get this, at least get a Pokemon that has a ground-type move. The electric gym will go much smoother if you use a ground-type move or Pokemon (or both).
Leonidas I was the leader of Battle of Thermopylae.
gym leader
beat 50 trainers
You have to win 7 times in a row
Battle Elite Four leader Bertha
First you have to battle the snowpoint gym leader
The eighth gym leader of Sinnoh, Volkner, returns to battle you again in Platinum after you beat the Elite Four. When you get to battle frontier, you and your rival have a double battle against Volkner and Flint, an Elite Four member.
Go to pastoria and battle the gym leader wake
crasher wake, water types. -seal339
the 8th leader in platinum uses electric type so i would recommend using ground type Pokemon..............if you don't have ground type Pokemon don't worry he isn't that good
The Gym Leader Name is: Volkner and the Badge is called Beacon Badge. In Pokemon diamond and pearl he has (Raichu, Ambipom, Octillery, and Luxray).In Pokemon platinum Voltner has (Jolteon, Raichu, Luxray, and Electivire) for his rematch he has the same as platinum but add on Lanturn.You rematch him in platinumBut if you want to see the Pokemon just go to this website ---->(http://bulbapedia.bulbagarden.net/wiki/Volkner)Have fun battling Voltner!!!! :D
U can't
talk to them again