the other day while packing my kite up i realised one outside line was attached to the middle knot while the other was on the end one. felt a bit off that day and was wondering if that would make a noticable difference.

Indeed it would make a difference - did your bar feel lop sided?
Measure your lines out, adjust accordingly so they are equal in length

if it didn't then you best be off to the doctors

i think one arm's longer than the other

I had a similar experience a few days ago, I crashed the kite a couple of times and generally just had a real unco day (even more than usual ).
Whilst standing on the beach talking to a mate I noticed that my bar was crooked and commented that one of my rear lines must have stretched and that was probably the reason I was kooking it.
My kite only has one knot on the back lines so I knew it wasn't a case of being on the wrong knot so I just went back out anyway.
However when packing up I discovered that the larks head loop had tightened up about 30mm or so above the knot on one side and that was the reason the bar was crooked. (nothing to do with the brand of kite as was suggested....MATE)
It amazed me how much it affected the way the kite flew even when I knew the bar was crooked and was trying to compensate.

TGMan, i got the guys at surf fx gold coast to do it for me. said it took him two hours. if i get a chance i'll post a pic tomorrow.