A clever concept, but at that sort of price it's not particularly competitive compared to a "standard" caravan. £27k will get you a Bailey Phoenix and many others of a similar quality. But I can see the appeal IF you live somewhere warm and sunny. That 2Kw heater will use some serious amounts of energy in the UK any time other than in the height of the summer.
We saw one of those inflatble caravans in France last year, a German family had it and towed it behind a converted coach,liked it because it was easy to store at their home.