Thankyou for your responses.
Once I got there , it was a tightly looped wool berber where the actual spillage was were black marks . THe customer had used foam and spread a brown mark 3 feet across!
I sprayed Nemesis on it , then left it to dwell , while I collected all my equipment from the van to the lift , moved the van to the carpark 300m down the road , then walked back to the job up on the 4th floor.
I extracted with my upholstery tool and all but the black marks came straight out. I had never seen black marks on a tea stain before , I went over it a few times with the buffer and the black was almost gone. One happy customer.