UK ? area prone to flooding, home insurance experience?

I?ve been looking for a place to buy; one of the 2 properties I?m looking at might be in the moderate risk flood area [according to environmental agency]. The blue field [if you know what I'm saying] of potential flood ends just around the property.

Then I?ve quoted Barclays and Avivo for insurance. They came back with insurance over 1000 pounds/annum.
Then I had found what insurer current owner have and had a quote of something over 200 pa [e-sure company] with them.

I?d like to hear your opinions what to do with this one.
I?d also appreciate someone knowledgeable what can happen in the future if my choice of insurers would be limited to only one?

PS the area is marked that it benefits from flood defences.
I have dropped the idea of buying this property now.
Thanks for input guys.
Why I was thinking about is?? Simply enough, Holland is basically below sea level and yet they are fine, probably better than Britons!
I?ve spent about 100hours on finding what to do with this one, including ASK.
Then [if someone would be interested] I found this:

http://www.floodpreventionsociety.org.uk/

http://www.floodpreventionsociety.org.uk/EXECUTIVE_SUMMARY.pdf

rather terrifying report from 2010!!!

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