Overview: Rachel and Jason head to a Birmingham BMX track to test the best in RC Motorbikes before putting the winner through its paces on a home built 'Loop da Loop' but will their bike and craftsmanship be enough to get them another place in the record books? Polly is on the east coast of America visiting twin brothers Geoff and Michael Howe, who have set up a business building military-grade armoured vehicles. After becoming the youngest duo ever to receive a military contract, and making the world’s fastest tank, they have clearly impressed the US Army. Will their ‘Swat Bot’ and Amphibious ATV pass muster with Polly? Jon Bentley is on the hunt for a bargain telly, looking at the 1080p HDTVs that cost under £300. With entry-level sets now boasting high-end features like 3D and TV-on-demand, are the manufacturers cutting corners or can Jon really bag a bargain? Janet Street Porter goes on a jaunt around south London, asking whether we still need to shell out for a satnav.