Designs for fast ignition demonstration facilities such as HiPER rely on predictions of the rapid heating of the DT fuel by relativistic electrons generated by ultra-intense laser beams. While there is much agreement on the physics processes underlying the transport and energy deposition of these enormously high current beams there remains a degree of uncertainty which can only be addressed by careful experiments with lasers very much smaller than would be needed for a facility such as HiPER. In many ways the smaller scale experiments are harder to model than the real ignition requirement and some of the physics and computational issues are discussed.