I went on a family holiday to Ibiza that year and couldn't escape the thing!!
Version-wise, I really don't know how I know this, but here goes:
The 'Los Del Rio' version was the official one, as seen on the music video and the one that got to #2 in the UK. Originally completely in Spanish, the worldwide release added said-Eurotart woman singing in the verses.
'Los Del Mar' copied the original, non-Eurotart version (with just the two guys singing in Spanish the whole way through) and was released in the UK, but only got to #43 here. It did, however, appear on that summer's 'Now That's What I Call Music' album (34) either as a mistake or because it was cheaper to license, I dunno.
Funnily enough, in Australia both Rio's Eurotart and Mar's non-Eurotart version were popular enough that Los Del Rio were #1 and Los Del Mar were #2!