Coffee roasting is done by profile. ie, you experiment, find the ideal roast profile for the bean, and replicate. If you can afford a machine that can replicate the profile for you then great. If not, you are stuck there with a temperature probe and a stopwatch, "Hand roasting"
Coffee roasters have a particular problem trying to generate the notion of "terroir" considering their "terroir" tends to be a concrete unit on an industrial estate, so that do it by claiming a 'relationship' with the grower. Expect photos of fangled toothed central Americans, perhaps even with their wives and children, stomping bare-foot on the red coffee cherries in the red-brown earth of the Finca (farm). Expect to pay a premium if your coffee bag has the word "Finca" on it.
There may also be claims that the 'relationship' involves development of the processing of the bean, at the finca, between grower and roaster. The reality, of course, being that the roaster chooses the beans from the same one or two UK wholesalers as everyone else.