Ian, I have
recent experience of this.
The EHIC will serve you well for local medical treatment but I also carry travel insurance supplied by NatWest, comprehensive bike insurance, breakdown cover and a further policy paying out in the event of me being hospitalised abroad.
After my recent incident in Belgium, I actually benefitted from carrying my EHIC. The other policies all proved useless, although the NatWest people spent several hours "thinking" before I made my own arrangements for getting me home (mate with a pillion seat). Getting my bike home also entailed a mate, with a van. While renewing my bike insurance afterwards I asked about extra cover for repatriating my bike, they thought about it for a bit before suggesting "mate with a van".