NFU want £150??

Another company was a great quote but never got back to me after talking to others, what everyone I spoke to seems to get stuck at is the fact that, if you wish to show it the odd times. What a performance of questions! Getting a vehicle insured is a doddle by comparison.
I suppose my main question is this, do you have to declare the fact you wish to show the portafold sometimes? or is it not important? They all seem to have a public liability built into the policy anyway, but will this cover things.
The towing show vehicle is not subject to anything extra, only a separate public liabilty though a club, this we have, but will not cover the portie, i have asked, I am now very confused as how to deal with it, advice greatly received.
thank you for looking
Maureen