Train tickets outward from Edinburgh: 9.30am on Thursday 22nd March
arrives in London Kings Cross at 13:55
Return Journey: Departs Kings Cross at 11am on Tuesday 27th March arriving in Edinburgh Waverley 15:24.
Both parts of the journey have reserved seats in the quiet coach. These seats were booked with a Senior railcard so you must have one.
This journey was booked quite far in advance so presumably it would cost considerably more to book tickets now.