Hello Steve and Garfield,
I am very much inclined to agree with your views regarding the longevity of caravans and fittings.
Unlike the car industry, the caravan manufacturers do not interact with their dealers in the same way, and as a consequence most dealer's areleft to fend for themselves when customers have problems. The result is that manufacturers are not fully aware of the frustrations that afflict customers, and until they do become better acquainted with the practical shortcomings of their products, shortsighted decisions about design, materials and quality of workmanship will continue to plague the industry.
Caravan designers seem to live in ivory towers, they continue to design new fittings apparently in isolation, when in many cases an existing proven design probably already exists in the general retail market. Examples of this, are the internal water pipes, which seem to leechout chemicals and taint the water, Taps, where seals break down and cant be replaced, door locks, window rubber seals etc.
I do wish there was some method of forcing manufactures to make improvements to products, especially where there is data that suggests a particular process or design has a long history of similar systematic failures. - A good manufacturer would be looking at such failures and working to establish the cause and affecting a design or manufacturing change to prevent reoccurrence as a matter of course.
Issues that should fall into this category would include: