I received this reply from Spain earlier this year. I had written to Queen Sofia in January to express my condolences on the death of her brother, King Constantine of Greece.
The envelope is the usual from the Spain Royals.
This stationary is different than what I have received from Queen Sofia in the past. The letter features her husband King Juan Carl's Coat of Arms on top. Most of the other replies I have received from Sofia & Juan Carlos were written by the Chief of Protocol and on Stationary featuring King Felipe's Coat of Arms.
This reply is personally written from Queen Sofia (although a form letter others received.) That would probably explain the change in stationary, however it is interesting that it is not Queen Sofia's coat of arms. Another point of interest is that Queen Sofia's name is spelt "Sophia." Sophia is the original spelling of her name. She changed it to Sofia, the Spanish spelling, when she married Juan Carlos. I can recall seeing the SPain Palace use Sophia before when releasing stuff in English.
And while this is a condolence reply from King Constantine of Greece, his name is not explicitly mentioned in the reply.
Palacio De La Zarzuela6th March, 2023
Ms.
Gertrude Alexandra Daly
[My Address]
From Her Majesty Queen Sophia
I would like to express my heartfelt gratitude for the thoughtful message of
sympathy, support and condolences you had the kindness to send me.
With my highest consideration and affection,
Sophia
I had written to King Felipe for his birthday and had shortly after King Constantine's death and had expressed my condolences to him in that letter. His reply did explicitly mention King Constantine by name.