If you're sure there is no "invisible stuff" at the far top left of the image have you tried saving an EPS copy of your image (through Inkscape) and putting that EPS in a Scribus image frame?
It might not be an ideal "fix" but it usually works for me.
My personal preference for vector graphics in Scribus is to use EPS in image frames, as opposed to importing SVGs. This gives you the dual advantages of (a) being able to resize the image more precisely, and (b) allows you to use contour lines for text flow. It's much more flexible but it does mean that you need two copies of the same image - but disk space is cheap and file searching is easy nowadays.
There may be technical reasons why importing an SVG is better - and I'm sure someone will rightly chastise me for saying the above if there are - but, for my simple needs, "EPS in image frame" wins almost every time.