O
Octopus
I think £70 is an ok price for south east England.
When they say "That sounds expensive", you could try saying "Well, that is the cost for me to get to your site and be there for up to an hour and I fix most problems in that time". If you want a call out, you could also try saying your price is £67 rather than £70. People will hear the sixty first and be mentally processing the price as being about £60 rather than being £70.
So where are you based?