The distance of a device from the master is limited with I2C. So if I want to expend the line to about three metres I assume I'd need a buffer. What device would be suitable and would it be an active or passive buffer?
This has been discussed on the forum multiple times. A search for "I2C distance" will return lots of info on how to increase the distance that I2C can reliably communicate. Such as, play with pullup resistor values, choose the proper wire, decrease I2C frequency, and others.
Search for I2C repeater or I2C extender.