You were right, the “Number of Characters Before Wrapping Text” setting did cause the long google url to have spaces in it. I have set this to zero and the URLs are now preserved.
However, if I just enter the google URL I get an unsupported type error. If I force the type using the above [media=....] tag then when I press play it displays "Buffering" and the play button changes back to the play arrow straight away (normally pressing play turns the play button into a pause button). Pressing play again changes the play button into a pause button, it clears the "Buffering" text too but it still does not play.
I have copied the url direct from the google page and the video plays fine on the google web site. Is there anything else I can try?