Made some progress tonight with new members/ potential members.
Due to problems installing Inkscape on Apple Mac, Tony paid £9 for Easydraw, installed that, & created a simple outline drawing, which he fetched along as DXF format on USB stick to test. We loaded it onto the laser cutter PC, & ran as a drawing, then as an outline cut-through image. It all worked fine, so Tony knows he can create anything else & cut it ok. He's interested in buying some transparent polypropylene from www.kitronik.co.uk & starting to experiment.
Frances brought along an image on USB stick, which I loaded, selected & Path > Trace Bitmap. I tried moving the 'top' image to the area being saved for laser-cutting. The DXF file was tiny at only 5kb, so maybe comprised only the outline rectangle we added? We tried loading the top and the lower image (as separate file), but it wasn't recognised.
Finally, Sally tested loading 1 of my JPG scanned sketches, & following the same procedure, including 'Remove Background' with Path > Trace Bitmap. We selected the paler of the 2 images after tracing/ We also selected Path > Simplify Path to reduce the file size (initially over 10Mb then down to 2Mb). We cut this at 11cm high, whereas the previous versionw as 20cm. The cutting lines are quite dense, and some lines still need cleaning off the source image, but it produced a strong image . . . .