Whilst it is rare for creditors to register Irish JM's on property in Spain, it is possible to do so. In short, I would sell the Spanish property as quickly as possible.
It can literally take years to sell Spanish property, unless you are prepared to heavily discount. Brexit has had a negative impact on the geographic markets where British demand is dominant, namely Alicante, and Malaga and the Canaries. Not only has Brexit reduced British demand for Spanish property, it is forcing some British pensioners to sell up as their pension income has been reduced by 15%, and there is concern whether they will continue to benefit from free health care if Brexit actually happens.
Jim Stafford