WW1 Buckingham Palace Letter ( from Memorial Plaque ) and Envelope marked

'WW1 Memorial plaque accompanying printed letter' from Buckingham Palace, folded and worn, with envelope passed by sensor date November 1917, which is addressed to 6 Hudons Buildings, Hendon, Sunderland. I cannot make out the name of the lady to whom it is addressed. On the reverse it states "Last letter but one" - How sad. Searching on the address only I came up with:

SEHMAN, JOHN JAMES
Rank: Private Service No:276211Date of Death:02/02/1918Age:30 Regiment/Service: Durham Light Infantry 1st/7th Bn. Grave Reference H. 6862.CemeterySOUTH SHIELDS (HARTON) CEMETERY
Additional Information:

Son of John and Mary Sehman, of 6, Hudson's Buildings, South Shields.

South Shields and Sunderland are neighbours, so I actually think this is the person to whom the letter and envelope relate, but cannot be categorical.

Code: 56367