Assuming that it is good, clean, pathogen free milk, there is no problem keeping it unrefrigerated for 3 hours. The milk should have natural lactic bacteria and short term you will get very little if any bacterial growth below 55F. I often pull my milk out of the cooler and let it warm up for a couple of hours before starting a make. Generally warms up to just 50-55F, but that way I don't use as much energy to heat up to ripening temperatures.
Many of the best European cheese use only natural lactic bacteria and don't even use starter. However, we do not know the source or how the milk is handled before transport. If it sits for 3 hours right out of the cow (warm) before he loads it into his truck, it might be problematic.
I'm still not at all comfortable with someone else adding an unknown culture and transporting unrefrigerated. Here in the states, it is illegal to transport unrefrigerated milk. At the delivery point, many groceries are required to reject a delivery if the milk is above 41F. Because, you never really know where that milk has been.