Does the 'halt' service include the 06.53/07.01 we're discussing? I think its going to struggle in its current format. Based on the totally unscientific basis of a couple of people I work with more people on the Oxford to Reading part of the journey are using it rather than change at Reading. For them its a much more comfortable journey and they get a seat. It also seems to be getting much busier at Twyford since I've been using it.
You could move the Henley connection back a few minutes so they get the next fast train although I can see that being unpopular as its slightly slower and 10 minutes later.