Just to go back to the £70 for a laptop repair for a minute. That would be 2 hours work (couldn't guarantee to get it dome in an hour so that's 2 hours work) so its only £35 an hour without the price of parts, not bad at all for a skilled job. You certainly would be paying about the same for a plumber call out or electrician.
Yup, also I've done a couple and some are a right bitch even when you know what your doing, and you can not charge too much or people won't have it done.