Same people who make sheds. I remember us wanting to look inside one at the NEC show and you had to make an appointment. Never bothered and the next year they closed up shop.
The SA one is a very robust off road caravan and as you say, the outside kitchen would not work in the UK, maybe in Spain. When we were in SA in 2018 we looked inside some SA built caravans as our previous SA caravan was a folder down trailer. What struck us was how thin the foam mattresses were as they were about 3-5cms thick. However the when buying a caravan in SA it came with everything ready to go camping straight away, i.e. battery, water and waste containers, crockery and cutlery. Cannot remember if awnings were inclusive. All you needed was bedding and towels.