Hi Robo,
Brad and I used one of the 26lt boxes this year in the boot of the MGF, bought it from woolies about £30. It worked really well although we did give it some help by putting 4 1.5lt bottles of frozen mineral water in, 2 in the bottom then the frozen curry, bacon etc the another 2 on top and then Butter milk etc on top of them - lots of room. As anybody with an MGF will know the boot gets pretty warm due to it location next to the engine!!! espcially with the overweight thrash down (oil temp was well up) but the cooler still worked well, we loaded it up Wed night and rand the cooler from the cig socket only when we ran the engine and the water was still cool on Monday (defrosted of course), and the food was keep safley chilled all weekend.
If it had been in a normal boot it would have been even better, the frozen water is always a good ideal anyway - why use ice packs - cant drink them.
Good kit.