Shaun "The Scientist" Ashmore

Wayne, on your next one try this: Pre-spray lightly with a detergent-free product that doesn't need rinsing out. Then, go straight over it with a rotary & bonnet.
After that, if the traffic lanes aren't 100% whack something stronger over them and bonnet them again, followed up by extraction with pressure down lower than normal and wand strokes a bit slower.
Doing it this way you may well risk a little moisture going down to the backing but only in the traffic lanes. Remember the shrinkage has to happen all over the carpet to pull off the edges. If it just pulls up in a narrower area the rest of the backing will take up the strain.
That's how I do it a lot of the time and get a great result without any problems. Much quicker drying too
