A few obstacles have surfaced already when we consider the effect of Brexit.
Prescriptions issued by UK doctors are no longer valid in Spain, which will have an impact on some. Also, if you want to buy a house there you now have to apply for a permit from the Spanish Military and submit a clear criminal conviction certificate (ah! more alliteration...) and some other stuff. Students won't have the same rights to work and live there as previously. However, the Spanish are still recognising the reciprocal healthcare system, so that's good news.