In reply to Murko Fuzz:
No good to you now, but when in an accident in Italy there was some debate of whether my wife needed to stay in overnight and the costs of doing so etc etc. EHIC card was produced and it was all 'bella, bella', fine to stay over, no further questions asked.
We did have to pay a small amount to take away a copy of her x-ray though but only maybe £10-12 (no charge for the original which I'm guessing stayed with the hospital records).