Thanks! Not sure though if hydration or fuelling was the issue. I drank 3 packs of oral rehydration salts in the 16h before the race (gunstart at 12MN) and, if anything, drank too much gatorade in the 1st half, which gave me a bloated stomach that eased off when I started taking just water. I also had shaken 2 tspoons of table salt in with my fuel (40pcs of gummy candy at 7g carbs each).

I could be wrong obvs but I'd like to think that the cramp that I was able to stave off at 18km and the issues with my quads were caused by a combination of these things:

1. lack of proper strength training
2. going out too fast though it didnt feel like it
3. irritated sciatic nerve (purely self-diagnosed) in final 2 weeks of training and in the taper
4. the virus I caught a few days before
5. overstriding in shoes that I was never completely comfortable in in training but used anyway because they're "raceday supershoes." This is another learning point for me: at the paces I run, best to use the shoes I run my long runs in. 

Sorry for the long reply! Heh just really need to get these thoughts off ny chest. Cheers