Have you tried using rehydration sachets to get your salt balance back under control? Food poisoning like that will throw all your electrolytes/salts out of balance and is going to take a while to get back in order. Your kidneys will be doing there best to maintain balance but a little boost from your diet may well help speed things up.
I use dioralyte in my training schedule already but haven't had any since my food poisoning. I actually went out running on Wed evening and managed to blast 5 miles in about 37mins on a very hilly route and felt very good at the end. So I think I am roughly back in sync after hovering up a load of food over the last few days. I guess we'll see up in Kielder but thanks for the suggestion.