that tyre repair stuff is excellent in my experience - it dealt with an inch square hole in a huge 4x4 tyre many years ago. i've driven on one of the emergency spares as well - in normal weather conditions it just takes a bit of careful driving and being aware that cornering is nigh on impossible. it also managed more than 50 miles and a considerable number of roundabouts and was still almost immaculate when it was replaced.
al, the rac can't supply a new tyre just change the old one, if you don't have a replacement there's nothing they can do. so make sure you've got some of that stuff in the glove compartment
