Originally Posted by Globaliser

Now that we have your travel dates, if we have your ticketing date we can look up the published fares on that date to see whether we can find a pair of published fares that matches what you paid.

For example, for purchase on 15 April 2017: TKW2S4C1 £1,230 (which is the round-trip value) combined with W1N0Y4C5 £2,986 would amount to £2,108 round-trip - and half of £1,230 is £615. That T class fare is the lowest non-DIF fare in the list for that ticketing date.

Originally Posted by gutt3d

Final info from me on this, in response to a question a little up thread - I booked my ticket on 16th Apr for travel on 7th May.