The lady from NFU I spoke to just suggested that if I had other policies with them it might reduce the premium. (I'm not a farmer)
My insurance has gone up, but faced with the pontential hassle of shifting insurance, I'll stay with them.
They've been very good over the years.
On a similar note, I got quotes for a small disposable hatchback I own, & it's now cheaper to insure that fully comp, than 3rd party