its £3600 per vehicle in your account for 3 months continuously, and you don't need an O licence for a vehicle with a gross weight of less than 3 tonns i.e. Merc sprinter, Iveco daily etc. If your credits good get a 0% interest credit card with 16 months to pay it back and buy you truck , gear etc with that. Get some decent software like CADS to do your estimates, its a big cost to start but you'll look professional and save time in the long run. Don't get bogged down on building sites ( they are inhabited by bricklayers w*nkers) and you'll need loads of kit. Go for quick turn around jobs like solar. Put you wife on the payroll as a director if she's not working ,she's entitled to earn 9k per year without paying any tax as are you. Remember not to buy a Range Rover sport in your first year and you should do ok.