A few days later I spotted another one of these creatures and managed to get a really good look at it after it had flown underneath a parasol. It looked like it had six legs to me and therefore shifted it from being a bird to an insect. I had a look on t'interweb when I got back to Blighty and found that what we were looking at was actually a Hummingbird Hawkmoth (which you can read about here) an insect commonly mistaken for a hummingbird and thought to have come about by convergent evolution where unrelated species develop similar characteristics.
Regardless of whether it was a true Hummingbird or a Hummingbird Hawkmoth it was certainly a beautiful little creature, and a delight to watch - one of those little moments of magic that you find on holiday!
I have a few more videos to load up, and I'm in the process of categorising and editing them now.