Copyright protects the form or manner in which an idea is expressed rather than the idea itself; Copyright relates to originality and creativity in artistic work rather than the physical artistic work or article itself, therefore if you were to be making exact replicas or reproductions of the candles you would need the permission of the owner of the idea to avoid breaching copyright.
Copyright law does not prevent the use of the same idea embodied into a product if it isn't an exact copy of the original work, so you would be unlikely to be in breach under the Copyright Act according to the information you have provided. Copyright law recognizes that an artistic work (eg.. the original candle design) might give rise to a corresponding design of an artistic work (your candle design), in relation to the original artistic work & it does this by incorporation of the legal principles within the Commonwealth Copyright Act 1968, Division 8
The Trademarks Act 1995, on the other hand, protects works such as logos, pictures & words that distinguish one work or product from another (think NIKE, Coca-Cola, Big Macs etc) & provides protection for owners of already registered trademarks related to particular goods & services. The Act grants exclusive rights of an owner to use & authorize others to use a registered trademark, therefore, permission from the owner would be required if that were the case. Well-known trademarks such as those mentioned above in brackets would be infringed by a user if trademark use was substantially identical with, or deceptively similar to the trade mark registered.