We demonstrate the growth of graphene films on nickel substrates by chemical vapour deposition using acetylene at temperatures as low as 750 degrees celsius, opening a viable route for its scalable production. Raman spectroscopy was used to confirm defect-free mono and multilayer graphene at and above this temperature, and of defective graphene at lower temperatures. Atomic force microscopy and scanning electron microscopy performed directly on the films give an indication of graphene flake size, morphology and also the topography on substrate. An unexpected dependence of graphene thickness on precursor dwell time is reported. This together with low temperature growth suggests deficiencies in existing growth models and hints at a more complicated growth mechanism.