Tidying up Radio Downloads

[Budge]

Slightly OT but GiP users will be familiar with the problem of finding 
several minutes of the previous programme on their GiP .m4a downloads. 
What I would like is to be able to edit out the unwanted material.

I would be interested to learn if others have this problem and the 
purpose of this post is to ask advice on what is best (linux) software 
to use and method for editing GiP recordings.

Alastair.