Paddle shifter down not working SMG 2003 M3 E46

Bought a July 2003 build SMG 6 speed sequential from a BMW lover..... WOW 3 days ago. Bought it in Melbourne Australia 2000 klms from where we live on the Goldcoast Queensland. Flew to Melb and picked it up. Drove it in Auto for the drive to friends place ( soooo scared ) for an overnight stay and then drove it back to the Goldcoast over Sat with a stop in Dubbo after 925 Klms and 998 Klms Sunday to home with my wife Carla ( the hoon) who has a factory M-Spec 1997 Cabrio 328i (125000 klms and as tight as). Never tried the paddles on the way back and now find it does not down shift but upshifts perfectly. Have a great Mechanic ( 20 years as a golfing buddy and friend ) here and have a BMW specialist next door to him. My question is what can be wrong with it as it clicks but no downshift?

Bad switch or disconnected wire is my first guess.