her name was fifinella

No, her name was Greta. Fifinella was a character invented by Roald Dahl. Sorry, my father told me stories about fifinella from the day I could remember (before Ro Dahl). The female gremlin was definitely Fifinella. She and Widget and Flibertygibbit (who were both male, one of them being the Spade Nosed Gremlin) helped to destroy airplane landing fields in Great Britain during the war. I am 60, and I remember these stories when I was no older than 5.