Good attempt there, Dan
Actually, it's pretty good
What you have there is eggy stars, probably caused by a combination of your image train not being aligned exactly with the optic axis of your scope and some field curvature. What you need to do is play around with your camera and extension tubes/spacers a bit to get them square on with your focuser. That, and to invest in a field flattener (a Baader MPCC would be the go). They're not overly eggy and for what you describe as "OK" polar alignment, it's a good piccie
As for not finding M83...make sure you get a good polar alignment, spend a little time on it doing a good drift aligning routine. Then, train your goto...do a 3 star alignment and make sure you centre the target stars in your eyepiece then enter each alignment. That way, you'll make sure that the goto will work properly. It's then just a matter of dialing your co-ords for M83 and it should take you there