Deep cleaning a house is jolly hard work and I think £15 an hour is OK, I would't want to do it for less. You would have to clean all windows inside and out, wash all tiles in bathrooms and floors in bathrooms as well as descaling if necessary taps and shower fittings and cleaning the loo and behind it, same for basin. And the work needed in a kitchen could take 3 hours on its own easily, cleaning out fridge/freezer, oven, extractor hood, tops of units plus units themselves inside and out. All light fittings in the house washed and polished, curtains vacuumed, every piece of furniture pulled out to clean under and behind, pictures dusted, doors, architraves, skirting boards all wiped down. And that's just off the top of my head without starting on the bedrooms. I wouldn't want to do it that's for sure.