Thanks Semerka. We lived down there (near Garmisch) for a couple of years hence are visiting old friends. It's a relatively brief visit as my wife cannot get more time off work, but we are stopping at Eschweiler (near Aachen) and then Baden-Baden on the way down, and then Cochem (on the Moselle) for a couple of nights on the way back.
We've never been to the Czech Republic (it'll probably have to wait until we are both retired!), but used to live in Romania/Bucharest - our route there/back took us through Hungary and Austria but if we'd had more time it would've been fun to deviate further North.
Anyway, I hope your car gets fixed and returned with the minimum of fuss