Charlie gets stuck in to an eco-build on the banks of the River Severn. Ele and Steve George could save themselves a cool £50,000 and it should be a fast build - but manufacturing hold-ups and bad weather soon throw things off-course. Then they have the added complication of juggling both a new build and a new baby. To provide a boost, Charlie sends the couple to visit one of Britain's most energy-efficient self-built homes.