The tap outlets are cast into the tank as it is being manufactured, which makes them very strong and robust.  Because of this, the outlet positions are set.

If you would prefer a high tap outlet on the left hand side, you can add a 'goose neck' to the lower 1" outlet to raise it up to an accessible height.  Water will only come out of the tank to the level of the tap, so you will need an additional outlet in the lower points to access the remaining water.

It is possible to drill through the tank and install additional outlets using standard tank fittings, your rain harvesting supplier will be able to advise on this. Be aware there is a chance of leaking if not properly installed.  If you are going to attempt to add an outlet, you must select a flat area of the tank [not a curved area].