In this week's look at the popular music scene Derek Jewell plays songs from Whole Oats, a brilliant early album by the American duo, DARYL HALL AND JOHN OATES , only recently available in this country. There are also songs from the new album by BRIAN PROTHEROE , who this year has won a wider reputation in the stage musical Leave Him to Heaven, and the electronic sounds of LA DUSSEL-DORF, a new German band formed by KLAUS DINGER , once of Kraftwerk: records