Matt
With all due respect, you are showing the same approach to business as the prospect. The only thing you are both talking about is PRICE.
When surveying and quoting, you need to talk about the cleaning process, why you would do this, that and the other. The cleaning solutions you use (I try to avoid the word "chemical". The techniques you use and how all the processes combine together to make a Cleaning System that is effective, safe for you, the customer and any children and animals, that the products you use CANNOT promote resoiling and will not damage or remove any protective treatment on the fabric and is quick drying. You will have examined the suite and fabric, opened the cushions and looked inside, examined the chairs for damage, wear and excessive soiling, test for fibre type if necessary and asked about the history of use and cleaning.
Or a briefer description is that you SELL yourself and your business, you don't just quote a price.
You need to set your own standards, your own goals and work to them and charge accordingly. You shouldn't be concerned about what others are doing or charging.
I'd have done all this and quoted £120.00 for a HWE based process so your price is in the ballpark for a quality service.
Safe and happy cleaning
Ken
PS Even then, you'll never win them all