I have a cleaner who does ironing, and she is paid at the rate of £10/hour (within M25). She is an excellent iron-er, but not very quick, and she would typically do five shirts, four t-shirts, king size duver cover, 4 pillowcases, king size fitted sheet, tablecloth, a skirt, pair of trousers, single duvet cover, pillowcase and two or three children's long sleeve t-shirts in three hours.
If she were ever to leave us, and I couldn't get anotehr cleaner who did ironing, I would be looking for a weekly service like yours. But it would have to be a service who collected and dropped off, would be willing to do that when I wasn't it (I would provide keys), didn't smoke and had a two day maximum turnaround.