Hi Keith.
To be successful in London you need some capital - accomodation is expensive and the cost of living is higher.
There is a huge number of EU plumbers and builders working in London and the south in general. They manage to undercut the competition and work for far less than the going rate.
If you believe that moving away is the right thing for you, you need to plan it carefully. Have you got good references? If not, try and get a local job for this very purpose. You could at the same time take on your own work and build a business up locally.
Your lack of driving licence is a problem but can be got around by hiring help, as you have said.
Look also at the big building companies - they may be willing to take you on, especially if you don't have family ties and are able to work anywhere in the UK. There is a building boom at the moment, so this is a good time.
Good luck!