The file saved on jane's kay folder has duplicated elements stacked over each other in it. This .dxf file should be have no overlapping layer on it and can be used by the laser cutter software.
Here is the Inkscape file for trouble shooting.
A trough needs to be built to sit below the waterfall, collect the water, and funnel it away to the tank that the pump is sitting in. It needs to be ~2.2m long (the length of the waterfall + 0.2m splash zone), ~0.4m wide, and ~100mm deep. The bottom of the trough needs to be raised ~0.5m off the ground (or at least, to a level safely above the required submerged depth of the pump).
To cover the trough need material that is waterproof and more robust then black bin liner.
Grace suggested: Garden pond material.
A frame needs to be built to hold the waterfall. Currently the idea is to make the 4 black shelving stands (currently in the storeroom) into two A-frames. Each A-frame would be made by tilting 2 stands towards each other and bracing horizontally. These then have to be joined together at a fixed distance of > 2.1m (the length of the waterfall itself).