Looking at the brilliant LCD on the back of the camera after a couple of test shots, it was obvious that the colour of the wall was a little more yellow than was apparent to the naked eye. I shot a frame with a piece of white paper in the man's hand so that I could do a custom white balance. The net effect of this was to send the daylight behind them and any areas lit by the ambient a little blue - not an unpleasant effect.It was clear that they were enjoying being photographed and were happy to indulge my usual technique of playing around with lenses, compositions, exposures and lighting positions.
I was trying to shoot with a wide lens under the cover and the shot that you see above was taken with my 16-35 f2.8L right at the 16mm end. I usually try to shoot at 200 ISO and the meter reading for the sand and sea behind the couple was 1/125th of a second at f5.6. I altered the output on the flash to give me f5.6 on the couple and changed the shutter speed to 1/180th to marginally underexpose the background. The available light reading on the couple would have been 1/30th at f5.6 so they were lit exclusively by the flash. I shot a lot of different images with similar compositions before changing over to a 70-200 f2.8L IS lens.
I moved my subjects so that they were leaning in the entrance just as the light outside was getting a bit better. By the time I shot the image below the shutter speed was up to 1/250th of a second but not really underexposing at all.