South Wales is the destination this week for Peter Powell as 1 On the Road and an audience of 1,500 visit the Mayfair Suite , Swansea, with top bands Ultravox and Level 42. From the beach at Tenby, Peter also takes a break from the Radio 1 Roadshow week to tackle his D J Challenge and introduce the mystery Roadshow band. John Walters takes to his bike for a trip round Wales in search of more off-beat characters to join him in Walters' Weekend. Sun, sea, stars and summer sounds-all part of a fast-moving 30 minutes to put you in a holiday mood.