In this video, Mich Turner of Little Venice Company (LVC), demostrated how to tier cakes using dowel rods.
She also gave a tip on inserting the dowel rods by twisting it into the cake so as to minmize the hole size.
She went further to say that you can smell the dowel rods to identify the cakes after being covered with fondant and also to determine the freshness of the cake(such lovely tips).