Ok Ive now finished turning the two tanks (the smaller one I've left a square block on the bottom so it looks like its sitting on top of a stand).
The large tank has had half of the bottom removed. Use a coping saw or band saw for this.
Ive also cut two small pieces of MDF and attached them to the top and bottom of my base. This finishes off the draw (except for the handle of course). Just for extra decoration Ive also cut two lines in the base to make them look like panels, you could pre-cut these and then space them out on the base or simply use a chisel or band saw to make the marks.