Postcard sent from Kent in September 1943 from Martin to his Mother.
The picture may be a coloured line drawing or a hand tinted photograph of a Horse Guards’ Parade in London. Please leave a message in the comments if you have expertise in the making of these types of pictorial postcards. We want to find out as much as possible.
THE GREAT FERN STREET POSTCARD MYSTERY 
Not to his mother but to his wife, Edith nee Swinburne. He addresses her as Mrs M.C Crosby – Mrs Martin Cook Crosby. Martin’s middle name comes from his mother, Ann Isabella Cook.
What is he doing in Richmond and Sidcup at the height of the Blitz? Was it his work or the heat that left him felling “tired and sore”? What is the “backing costume” that he wants in preference to the pullover?
Ah, got it. I think “backing costume” is “bathing costume”. He’s looking forward to a dip to ward off the heat and soothe his tiredness.