Paul, to answer your query re water ingress. The seal around the midline trim and the awning rail are considered to be good for about 10 years so factor that in and get in early. Something we didn’t know until after we had the issue ☹️.
Another weak point, not one we’ve suffered from, is the high level brake light apparently.
These are exceptions rather than the rule, there are old Eriba’s out there that have never had any water ingress issues. From what I hear of other marques of caravans they are far worse.