We have developed a stitching interferometer for use with large optics, such as those used in Laser MegaJoule and NIF. The idea behind this technique is that, to keep resolution at its highest value, a 'small' aperture phase-shifting interferometer must be used. But this means that measurement of the complete component has to be performed by stitching the individual sub-apertures together. We have overcome most of the obstacles involved in stitching interferometry, and have been using one such system at our optical and laser production facility in Orleans for some years. We have previously reported transmission measurements performed on a Phebus laser slab. We present here measurements performed on Laser MegaJoule transport mirrors measured in a horizontal position, and on glass inhomogeneity without oil plates. This latter requires multiple takes on each sub-aperture, and additional computing, but the whole process has been automated. In addition, we contribute to the pretty picture department by showing graphical results perhaps never previously seen. This work was performed under contract from CEA-LV, as part of the Laser Megajoule development.