Renee - if you really are up against time limits then buy a PADI OW manual, RDP and videos from a local PADI shop and study them all at home. Don't worry if you don't know what these terms mean - they will and you will once you've watched the videos and read the manual.
Do the Knowledge Reviews at the end of each of the five chapters (use separate sheets of paper, don't ruin your manual) and bring them with you. Better still, do them in emails and send them to your chosen dive center ahead of time.
Then, when you arrive there'll be an hour or so reviewing the KRs and chatting about diving generally, a half day spent in a pool or shallow water (your holiday's already started!), and two half days spent doing actual dives. The only classroom work will be the exam, which takes an hour or so and can be over a beer or two after the day is over.
The other benefit of this is that it won't cost you any more than doing the complete course with one dive center. Doing any form of referral means paying two dive centers, which always works out more expensive.
This really is the most painless way to learn to dive, and takes the minimum time out of your holiday. The four training dives are at sites that people choose to dive at anyway, and you'll see the same sharks/rays/turtles/groupers/etc that they will.
