Photo three - no expensive resin products here! The Fastglas resin and hardener are available from Halfords. I mix the two parts together (usually too much and also more hardener than recommended) in a plastic cup, before pouring in to the mould.
Photo four - the resin poured in to the mould. I do not use a release agent and once the resin begins to jelly, I place a piece of plastic card over the top of the mould and press down, forcing the resin in to the mould which also produces a flat back.