In the short story Mr Eastwood's Adventure, Mother Gibson managed a shop selling second hand glassware at 320 Kirk Street, a street that had many antique shops.
According to Inspector Driver, she also rented her upstairs room to people who wanted to meet in private, usually lovers. At the beginning of the story, writer Anthony Eastwood receives a phone call from a stranger, a woman named Carmen who told him that it was a matter of life and death and to meet her at the address of Mother Gibson's shop. He was to gain admittance to the upstairs room by using the codeword "cucumber".
Mother Gibson was described as a very old lady with a truculent manner. She had "a budding moustache that many an undergraduate might have envied."