Finally, I am posting photos of the completed chicken house! It has been operational for about a month and a half now, and the chickens are now much bigger than in these pictures.
I can confirm that it is working well, with a feeder made from a recycled kerosene burner, the drinker installed in the wall and also poweraid bottles which are perfect chicken drinkers! It looks like a stained glass chicken palace now, and is a bit of a local attraction.
I can also confirm that it is definitely mongoose proof, dog proof, pig proof and cat proof! Ahhh, the sweet smell of success! Next post on this will be pictures of the rescued battery hens which are now happily laying an egg each a day! Thanks for the encouragement.
I think that with the sheer weight of bottles and concrete (one 1 litre bottle filled with water weighs 1kg) that it should also be cyclone proof. Everything in the construction was salvaged except for the chicken wire. Hooray, about 1000 bottles not on the beach!