I just clean all carpets with HWE solution from Craftex, full blast, never let me down, wool, poly prop, axminster, you name it i'll blast it with this stuff, dont worry about pre spray, just scrub stain out with a wire brush and white spirit, too much time these days is being given to 'the right chemical' and 'a satisfactory finish',, just get in there, scrubbidy scrub, cash on delivery, no questions asked.
Dan