Some advice needed

Was thinking food wise that a 24 hour, military ration pack maybe the way to go. 4500 calories, mixture of sweet and savory food, snacks, sweets; you will not win masterchef serving this food but when hungry it tastes good! None of it will need refridgeration, food is pre-cooked can be eaten cold but you normally boil the bags in water (you will need a camping stove + saucepan). Think that no savory food for 24hours will be a pain. You can get them from an army surplus shop or internet.

Does that mean that you are expecting to do 100 miles (ish) each? If so that means a lot of standing around; and riding around a short circuit over and again. Am thinking entertainment (on/off bike)and keeping warm and dry? Training nutrition seems covered as above (raleigh). I did a brilliant endurance event too long ago (126 miles, 30 hours; kayak, cold, rain, hypothermia) with work colleagues, great experience. But we did a huge tasty curry which a 2am had no takers and looked vile! (Police were called to,"a group of dodgy looking men standing round a van looking v. suspicious"). Ask people what foods they like; I love cream crackers which are light weight,supprisingly calorie rich and can be 'done' in lots of different ways! Getting the food right will keep up morale. Good luck, let us know how you get on.

Just carb load in the days leading up to it, Pasta, Rice and Ketchup for Breakfast lunch and dinner.

Then don't bother with all that energy food crap, just take flapjacks and jaffa cakes with you.

And perhaps a gel for EMERGENCIES. But beware, they're proper ming.

For training, just do what you are doing, but faster. 5-10% more for a while.

Then rest a few days before and just swim or something.