Hi Roxy I checked out Smith's and no luck there. However I spoke to an agent in Cadiz, Spain, and the situation is thus:
A non-resident EU national may bring into Spain their EU registered car without further formality and keep it in their at their second/holiday home but neither they nor any other person may use it in Spain for more than six months in any year, i.e. if it is driven for six accumulative months it must be off the road (garaged, etc) for the remaining period of time. Any person who spends more than a total of six months in any one year in Spain is considered resident and consequently not entitled to the above facility.
The problem for ROI residents is this. Their needs to be an Irish Insurance company with an office in Spain to offer insurance in Spain on an Irish regd car. This is how UK vehicles are managing to secure insurance on their UK plates. Cornhill for example and others have Spanish offices.
If you insure here in Ireland and leave the car their, (some people have done this), technically the policy maybe void.
The only real alternative it seems is to switch the plates to Spanish. But this can have it own hassles including replacing the headlight units completely.