Guest,Dazbo:

In UK the 70 years runs from the death of the composer/author (or the later death if these are two people (Gilbert & Sullivan for example); or the relevent death if you wish only to use thr music/words.
If the copyright has been transferred to another person or entity, the same expiry is still effective. The original composer cannot grant, or sell, to a third party rights which he does not have.
For printed music, the publisher has a copyright on his layout for 25 years from publication. This means that if the author/composer has been dead 70+ years, and the publication is over 25 years old you are free to copy it. It does, however, prevent you buying one tidy copy of a Bach chorale and taking 20 copies for all your choir.

Hope that doesn't muddy the waters too much

Nigel