A bandolier is really nothing more than a belt with pouches or bullet loops on it. Likely curved where it goes over the shoulder so that it lies flat. I should think there are patterns out there, several on Etsy, but it shouldn't be too difficult to create your own pattern. Start with paper and an idea, move on to a prototype, et voila, you're a bandolier maker.
When you say "heads", do you mean the projectiles? Probably expensive in GB, but reloading bullets are available. Or if it' just for decorations, turn some on a wood or metal lathe.
It's crafting time!