Usually for this route I get a nice advance 1st from Oxford to Southampton then a standard fare from Southampton with Southern. As XC advances seem to have tripled in price at the moment (for 1st class) I find that a basic off peak return is now cheaper overall even in standard class and gives flexibility. Routing on national rail is either via Guildford or Winchester depending on departure time and 88 miles and 90 miles respectively so presumably falls into the shortest distance or less than 3 miles extra category and depending on departure are pretty much the same journey time, between 2h30 and 2h55. However, I noted that using XC and changing at Winchester as per national rail I then take exactly the same Southern train from Fareham to Havant as I would if I were able to continue to Southampton with XC and change there. It is however 7 miles further but of course only 1 change and less time waiting on station platforms with a 2tph service from Southampton to Havant versus a 1tph out of Winchester to Fareham if I am delayed for any reason. Routing via Southampton gives a journey time of 2h30 to 2h40 so at times is actually the quicker route. I am not leaving the station at Southampton so is there any real reason why a passenger (sorry showing my age, I mean customer) could not travel via Southampton and change just once as its certainly less hassle and at times, actually quicker. All the ticket says is "not via London", no mention of any particular route.