My neighbour recently rejuvenated his hood with some wonder product (can't remember what it was) - it was literally green with mildew and moss and is now looking like new.. so cosmetically at least they can be easily enhanced.
He also seems to have non specific problems with the tombstones not going down so check those.
Head gasket cost me £600 excluding skimming the head + VAT IIRC at a rather expensive MB indy. (No one on here).
Ade
This will most likely have been one of the Renovo range of products - they are all excellent.