On the Focus, the CC servo is mounted behind the engine on the bulkhead.

Internally, as well as the steering wheel buttons, visual clues are that there are 3 switches on the pedal box instead of 2.

Although an option only on the Ghia in Europe, its a standard fit from mid trim levels in USA, including the SVT (ST170). Quite common retrofit over here using a US sourced Ford kit. Got one on my FRS engined MK2 Mondeo.

The lower cut-in speed is ~30mph, but I've not found an upper limit yet - authenticated by off duty authorities on the M40.

Martin