Guys, thanks for all your advice.
Despite a friend telling me to "go for it" and that he used it on a Porsche (not his own), I see no-one here recommending a jb repair.
Why should I be surprised. I guess its what I wanted to hear!! heh heh!!
My first reaction was a weld repair, but now i think a replacement head may be the safest option. The welding may be a bit close to the valve seat, and requires a skilled guy too.
What does a new bare head cost from Mercedes anyone?
I will check breakers for a 2nd hand one tomorrow.
Thanks again
G