It doesn't seem to be just related to the space=preserve attribute i.e. if I add any attribute whatsoever to an element it does not display via the XML DSO "data islands" approach. e.g. <title>Mr</title> works whereas <title id="abc">Mr</title> fails.
Interestingly, if I take the attribute off a tag then the data for that tag appears with the data missing for the remaining tags that have the attribute which suggests that some (possibly all) of the XML data is being loaded OK.