There are 2 Tolkien Postcards in a UK Fieldings Auction on 16th January.

I’m not sure if these are suitable for the Letters section, but I couldn’t find them. Mod edit - have been added, thanks

Lot 31
Letter link: Letter from J.R.R. Tolkien to Allen & Unwin • 10 October 1957 (#2422)

J. R. R. Tolkien (1892-1973) – An autographed Merton College printed postcard in ink signed with initials, to Allen & Unwin Ltd. “Would it be possible for us to collect “Rocket” on Saturday morning (October 12th)? If I manage to come at all, this would be about 11.45 a.m. & this may be inconvenient or impossible”, 10th October, 1957.

NB - The Rocket mentioned may refer to the Rocket Statuette of the International Fantasy Award that he won for the Lord of the Rings from the 15th World of Science Fiction Convention in 1957. Tolkien said that he thought the rocket statuette “absurd”, but the speeches at the convention “far more intelligent”. He kept the statuette, which is still in the family’s possession.

Estimate GBP 500-800

Lot 32
Letter link: Letter from J.R.R. Tolkien to Mr Smith • 27 October 1957 (#2423)

J. R. R. Tolkien (1892-1973) – An autographed Merton College printed Postcard in ink, signed in full to ‘Mr. Smith’ “Thank you for your specimen facsimile, and for your kindness in thinking of me. I should indeed find these specimens of considerable use in Class-work and should be very grateful if you would let me have them”, 27th October, 1957.

Estimate GBP 500-800