In a previous life I have rented on a cash in hand basis on a six monthly basis; once on a 12 year lease but negotiated at the start being able to walk away at 4 years. And once on a three year basis.
Sometimes what you get offered is a cheap deal in year one with an unspecified rent review in year two/three and they'll want you to sign up for years.
Refuse and offer, say one year's commitment tops and be careful of having to maintain the insides to an "acceptable standard" when you leave. Check rates, leccy and water.
An informal "farmer" arrangement sounds good to me.
It is easy to get sucked into being a "Businessman/Director" We were turning over 25K a month, but after rent, vehicles and wages we (Mrs Gold and me) were working long hours for a pittance and paying employees more than we were getting.