The HSE informs me that if the EHIC for which details were provided by the Deputy has a validity date which predates the time of the treatment in question being received, then they should provide details of this card to the institution which treated them. The institution will then be able in a position to process the charges under the EHIC scheme rather than charging the individual personally.
If, however, the EHIC which the Deputy refers to in his question has a date of issue which is later than the period in which the treatment was received, then the person concerned should contact the authority in their competent Member State which issued the EHIC. The person should request a temporary certificate verifying that they had cover for necessary health care during a temporary stay in another EU\EEA Member State for the period when they were receiving treatment in this State. This temporary certificate may then be given to the institution of treatment who will then be in a position to process the charges under the EHIC scheme rather than charging the individual personally.