Help - Timing Chain Cover Leak M103

[Made in Germany]

Searched the archives but was unable to draw final conclusion.

My mechanic discovered a leak of the timing chain cover. He
admitted that he had not done a repair job of similar nature
before, but concluded that it was not a serious issue and can
be fixed at a later stage.

My car is a 300CE with the M103 engine and has done just under
75k miles.

Is this a big job to fix? Can and should I really ignore this until
some time later or will I risk greater damage? Can the Forum
explain what ideally needs to be done to fix this problem and how?

Thanks !