Hi names Greg , i have been cleaning carpets and upholstery in Leicester-shire area for the past 27 years, we also have designed and built are own cleaning system, the reason you may not see the business advertised is because we have reached the stage not required, it is repeat and recommendation.
The question [drying time] depends on carpet soiling, thickness of pile, temperature of room, power of suction to extract etc.
The most important part is the cleaning if you have done that well be honest with your customer tell them it may take 12 to 24 hours to dry.
We clean carpets with deep high temperature rinsing helping to destroy dust mites and germs, that's what the customer requires not the gimmicks of just quick drying. My contact no. 07930812873