A search seems to find a few suppliers but the pictures clearly show 4 cylinder not 6. None of the many numbers on the old box seem to produce a result. Seems to be plenty of offerings for the BMW 6 pot, I wonder if they are the same part.
A6429005801 looks slightly different to the one fitted, has there been a change to the design anybody know ? It shows on various lists as right for the C 350d and the connectors look the same.