I can understand your position,
Might I suggest you arrange to get the caravan surveyed by an AWS engineer. The engineer might be able to tell you if any other parts of the structure are in a poor condition and if they are likely to fail.
Until you know the extent of the damage and the cause, you won't know if it can be repaired, and if so how much work is involved and of course the cost. If the damage is localised and can be repaired, then it might worth considering doing it, as I'd guess the cost of repairs will be considerably less than buying another caravan, and you'd have the knowledge of the caravans condition and exactly how it all works.
I'm guessing your not considering a brand new replacement (of course I could be wrong), but assuming your looking at secondhand which is always a risk because you don't know what problems it might have waiting to surprise you.
Selling the old caravan may be difficult as it is damaged.