AW, I had the same issue with my doctor, so I offered to race her over 10miles for the cost of the cert (£35), we train at the same centre on a Monday, so she knew my training habits and let me off! Also at the BUPA health check I was diagnosed as having an inverted T-wave, which turned out to be because I run a lot, who would of thought!!! but I had to miss the tread mill stress test, which was a shame.
Regarding fueling Ruth's plan for me was amazing and I got through Paris without any issues, but did find the level in take hard, possibly the hardest bit of training. In the build up last year I switch from Go to Gu gels and it worked fine, for the same reason, they are a lot easier to carry.
Good luck at Wokingham