Cat Tax, business relief on an old farm house.

Good evening,

I recently inherited a farm and there is an old 2 bedroom farm house that was last lived in by my grandparents back in the seventies. . My father kept it in good condition and used it for storage over the years. As there is no one living on the farm, I have had to install the internet for the security cameras . I use one of the rooms as an office with a computer storing all the cattle cards/ bills/ accounts etc keeping it separate my own house , a few miles from the farm. One of the rooms is for power tools, medicines and sprays , one for an office , and kitchen to have the grub and the old tv room.
I don't qualify for Agricultural relief but I qualify business relief but I have been told the old house won't qualify for business relief because it is a dwelling .No over has lived in it since the seventies and therefore the insurance company will not insure it as a dwelling
It is used solely for farming purposes but if I decide to insist on claiming the relief on it , I am been told that I would be liable for commercial rates on it!
I read up that agricultural buildings are exempt from rates, I don't know!!!
Fair due to the father for maintaining it as he didn't want it looking like an eyesore when driving into the place and also it acted as a deterrent for nightly visitors looking for tools.

Has anyone else been in a similar situation regarding business relief and what did ye do?

Thanks.