No point cleaning for £10 or £12 per hour, you're self employed, there's always travel time between jobs and many hidden costs involved in running a small business.
Those type of rates do not bring you even min wage as your actual hourly wage once your business costs are deducted.
Also don't forget it's such physical graft you cannot sustain a heavy schedule for as long as a desk job and when you do flop back onto your sofa, there will be admin to do, calls to take from clients and all sorts of work to be getting on with for the next hour or two. It's not an easy option no matter how much you charge so why be cheap?
As you can tell, I used to clean and I do know a fair few professional cleaners and cleaning business owners and it's easy to charge £15 - £20 per hour as long as the service provided is good and reliable
If, and only if you do charge these kind of rates will you be able to make a proper go of it and earn a decent living at the end of each day.
You learn all this with experience, if you compare it to when you were employed at a previous job, what sounds like a lot per hour at first is actually not even worth charging, you need to cost everything out first and then decide on rates, you'll always need to charge more than you thought.
£10 per hour is a pointless amount to charge and boils down to peanuts really.