RR - Interesting point, as one of the people I spoke to mentioned the word 'competitive' although to be honest I didn't listen properly! Then again, another company definatley said Marathons are not covered, but running is, and there was no option to add-on dangerous sports cover.
UK - Yes, the EHIC (Previously E111) will cover you for health care within Europe, but...It won't cover you for emergency transport home, or even assisted medical travel.
Incidentally, I also have travel insurance through my bank, but it doesn't cover the rest of the family...They wanted £44 just to add my wife to the policy, compared to around £15 for a new policy from else where covering both of us!