Thanks to your reaction to the quotation I received yesterday for the end-of-tenancy clean, I sought a second professional opinion. A firm in Reading told me that the normal charge for a one-bed flat would be between £140 and £170, which would include insides of windows plus guarantee. The guarantee aspect means that if the letting agent is insufficiently satisfied, the cleaning contractor will return free-of-charge to ensure that there is no deduction from the deposit for further cleaning. Nice touch.
Yesterday's quotation also included both of those aspects, plus a professional clean of the oven. The firm in Reading said that for an oven clean one would expect to pay an additional £50, so I took time out of my packing today to clean the oven.
I don't think this requires another £50 worth of cleaning, do you? Please be honest, I know I can trust you.