No they won't because people expect to pay that kind of money for a computer technician. Just like they expect to pay £50/hour to an electrician or a plumber. And the prices are that high not because our industries are a rip off, but because that's how much we need to charge to make a decent living.
Lets assume you want to make £15,000 a year profit based on your old £15/hour rate Andy. That is £19,120 you need to bring in before tax and national insurance. Plus your business expenses (car running costs/advertising/insurance/office supplies) means your gross income needs to be around £25,000 (based on my last years business expenses). At £15 an hour you would have to work 7 hours per day to make that kind of money!!! Bearing in mind in that £15,000 you now have sat in your account, you have to pay the rent, gas, electricity, council tax, telephone/tv/internet bills...Even if you were to somehow get 8-10 hours a day, that's still not enough of a salary to get you a good mortgage. It's just not feasible to do 7 hours a day as you would then be spending many hours travelling between jobs and then doing the admin side of things when you get home aswell as contacting people who left messages during the day. My heart is twinging just thinking about all that work
You need to do some calculations and see for yourself just how much you will make at different hourly rates. I understand you may not have rent/mortgage/bills to pay atm, but you will one day.