I originally posted this question under Transportation with a slightly different title and a longer description. It was recommended that I move it here.
I've been marching through National Rail as days in May become available for buying tickets and I've saved a lot of GBP by buying in advance. (I admit I was ignorant about how National Rail works, and was surprised when I had to go somewhere else to actually buy the tickets.)
I hit a snag early on involving a trip from Moreton-in-Marsh to Bletchley. I found the exact route I want, but National Rail bumped me to London Midland to buy it. When I tried to do that, I got error messages twice. So I tried to get the same ticket through Great Western Railway, but GWR does not show the option I want which has only 2 train changes. All their listings have 3. In addition, National Rail shows a price of 30.10 GBP for the journey with a Senior Card and GWR shows a price of 35 GBP.
I did a Live Chat with someone at GWR who told me that the National Rail option I want does not meet "guidelines" and recommended that I split up the journey into 2 segments, going to London first, then from London to Bletchley. I don't want to do that.
The 2 change route I want to take is: Moreton-in-Marsh to Oxford on Great Western Railway, Oxford to Coventry on CrossCountry, and Coventry to Bletchley on London Midland. This is an excellent example of how a seemingly simple (to me) journey can get complicated. It takes longer than the 3 change option, but I don't mind that.
When I split this journey up, the advance Senior Card price from Moreton-in-Marsh to Coventry is 8.65 GBP for the exact same route and time. National Rail bumps me to CrossCountry to buy the ticket. The train on to Bletchley is 3.30 GBP. London Midland is the ticketing option for that part, but in this case, it seems to work. Doing the math, the total price is 11.95 GBP, a little over 1/3 of the National Rail price for the same trip. Both CrossCountry and London Midland quote the same prices as National Rail.
Does anyone know why this works this way?
Is there any reason why I can't or shouldn't split up the journey into 2 tickets? I really would like to get the route and number of changes I want, and now that I know about the prices, I also want to take advantage of those much cheaper tickets.
The answers to my questions may help me make better decisions on the train tickets I need to buy in the near future.