Great Western Coffee Shop

I sent this enquiry through to GWR Customer Services a couple of months ago and haven't heard anything back so I thought I'd share my concerns in case anyone else wants to checks their pricing from different locations...
 
4 years ago I flagged to you a ticketing discrepancy which meant that 1st Class Eastbound-Only customers from Maidenhead were being overcharged.  You accepted that this was an oversight and issued compensation.  This was also reviewed by Passenger Focus.  I have noticed that the same discrepancy exists on your 2017 season ticket pricing, specifically:
 
If I have a Standard Class ticket with z1-6 travel it costs £3796, and without z1-6 travel it costs £2988.  A difference of £808.
If I have a 1st Class Eastbound Only ticket with z1-6 travel it costs £4592, and without z1-6 travel it costs £3744.  A difference of £848.
If I have a 1st Class ticket with z1-6 travel it costs £5292, and without z1-6 travel it costs £4484.  A difference of £808.
 
Please can you explain to me why someone, like myself, who has a 1st Class Eastbound Only ticket is being charged more for the very same London Underground travel as a Standard or 1st Class passenger.  If this is a repeat of the oversight then please can you take the necessary steps to refund all affected passengers.