I've only just come back to this and still need help with some clues, which may have an extra word.
5A Remote island could become boring.
7A Those at the margins about to abandon lives.
19A Group of plants stocking anonymous shell business with source of rubber.
Also, could anyone give me some tips as to filling in the grid ? I have the obvious top and bottom across and top right and left down, and the long across in the middle, but I have never done a grid of this sort before, and am rather lost !
Thanks.