Welcome to the Bunnings Workshop community. Thank you for joining us and sharing your question about mounting your towel rail.
I recommend using the Ramset 8 x 50mm Universal Anchor - 4 Pack. You can purchase it as a bigger pack in case you need more anchors. It is an ideal anchor to use especially if the FC sheeting is tiled at the front. Please observe the recommended type and size of the drill bit for the set you purchase.
If you need more advice and information please let us know.