In reply to Rampikino:
I've suffered quite badly on both hilly trail, and flat road marathons.
I've read a lot of good things about the hotshot product linked above, but difficult to know how many of the reviews are truly independent.
I'd be keen to test it, but unfortunately the company only has one distributor who will post internationally from the US, and their postage charges are expensive. $65 for 12 bottles of the stuff, plus another $30 for delivery, then possible import duty to pay as well. A lot of money for something that may or may not work. Still tempted to go for it though.............
I've contacted a couple of UK companies who specialise in sports nutrition to see if they could become UK distributors, but no joy yet.
Post edited at 13:38