They might sell it in your Morrissons Kate; it's often down the beer aisle and I guess you don't look there?
Oh dear Ben, you've just sent MK to the alcohol aisle. She'll be there forever, surrounded by empty beer bottles, with the odd emptied jerky packet. She is lost forever.
Don't think biltong has much nutritional value and it is expensive to boot, a bit like chewing dried camel dung.
Biltong is like a spicy jerky so has similar nutritional value as jerky. It is basically dried red meat since the drying process is over a low heat I would expect it to have nutritional values close to the original red meat used. Now if my basic nutition knowledge is correct, aren't red meats good for the range of vitamin Bs? In that case jerky and biltong must also be a good source of the vitamin Bs, which as you will know is needed for energy in some way. Also it has proteins and fat, all needed by the body. Also protein and fat are good sources of energy, especially fat. In fact if you don't push yourself hard while walking it is probably fat you are burning most of. IMO on a cold winter camp high protein and fat foods are good as a last thing snack to provide internal heat from thermogenisis as the food is being digested. Peanuts and jerky/biltong are good sources of this.
BTW anyone see that hotest place pseudo science show on BBC last night and recent episodes? The male tv presenter (formerly one of the trainee vets on that show following one year of the students before qualifying, you probably only remember the attractive blonde Scandinavian student Trudie Mostue) got Kate Humble (marine biologist and science tv presenter) to dip her finger in camel urine and taste it. He dipped his middle finger and tasted his index finger. Classic trick that. Works with anything nasty. Camel urine is supposed to be very concentrated and thicker than human piss. Probably tastes no better than your camel dung Tim.