Thanks everyone, makes an awful lot more sense now, I thought that a hot start was where the engine hadn't been given enough time to cool, rather than a lack of power in the starting system.
Leading on, if your flying an SET, caravan, porter etc, isn't it vitaly important to get the engine running first time, and also to have a suitable trip distance to recharge the batteries in order for the next start? I've got a few friends doing bush flying in those types and they tend to do short trips, or have manufacturers taken this into account?