Disappointed Insurance information

Very disappointed when talking to the Club regarding renewing my caravan insurance to find that they had incorrect information regarding replacing our van under the New for Old cover. When I checked the amount with them that would be needed to replace our existing Sterling Continental 580 the representative tried to tell me that the cost of this van had reduced since last year. When I queried what replacement van she was basing this figure on she advised me that a NEW Sterling Continental was cheaper than last year. When I tried to advise her that this was not possible as Sterling brand were no longer made she continued to insist that it was listed in her guide and was that the sum I wanted to insure for? Even after referring to her manager she was still questioning me as to why I needed a higher amount of cover despite me telling her that I would need to purchase a Swift Elegance model to have an equivalent caravan. After much discussion she quoted me for the figure I felt was required but I found this whole episode worrying. What would have happened if I had accepted her advice then needed to make a claim ? Would they have paid out to replace my van with an equivalent one or would they have said I had under - insured an refused my claim?  Needless to say I've been busy checking other providers.