Never less than £10 an hour.
Our amazing cleaner has been with us for almost 8 years and I tend to give her a small raise every Christmas, along with a £100 xmas bonus.
She comes 4 hours on a Monday, 2 on a Friday, and we give her £100 a week, so it's almost £17 an hour, but I pay more for the convenience of her coming on a Friday for only 2 hours (which involves travel time of almost the same amount. She frequently stays beyond her time if there's something that needs doing, and she knows us and our house so well we barely need to even tidy up before she comes.
This year I've also started to pay her for 6 weeks holiday as well, as I've realised she's effectively on a zero hours contract and that makes me feel uncomfortable. I think she deserves to be able to rely on us for income.
To be honest, we'd really be lost without her, so I pay her really well in recognition of this.