hi Laszlo, thanks for the reply;
i actually posted the wrong image; that one was the first one i did and i also noted the slight difference so i changed it and tried again (see updated attached image) with no difference.
the 'tags' have been added using the annotate function in the schedule window - as far as i'm aware, this is what the annotate function is supposed to be for, adding text/dimensions etc. to the basic view that's automatically generated. if annotation is affecting the layout, i think its a serious flaw in the functionality of the tool. however, i don't think this is what's causing the problem but i still have no idea what it could be.