High Energy Transmission Laue (HETL) is a new synchrotron X-ray diffraction technique we have recently developed. It allows the lattice distortion of individual grains within polycrystalline engineering components to be probed. Because it uses much higher photon energies than conventional micro-beam Laue diffraction, larger, real-life engineering components could be measured. Our research focuses on refining this technique, and on improving its spatial resolution and accuracy. These developments are carried out at the Diamond Light Source, the UK synchrotron.