Ever seen the infomercial on Super beets?. It's the real thing. YouTube this product. The surgeon on botched has used a beet powder in the operating room for a sustained energy unlike N.O.S. etc which leaves you jittery and waiting for the crash. Athletes are aware of the advantages of beet powder supplements.
Thanks everyone for the advice and helpful suggestions. Was a 3 hour set with no breaks but made it through with a litre of lucozade and wine gums. Also adrenaline seemed to keep the engine ticking over.