If the characters are unfamiliar it's because all of the contents of My Cartoon Annual are reprints from Spanish comics, translated into English. The book is copyright Opal Quill Limited, and was printed in Spain. The company also did a few adventure comics annuals (again, all reprint I believe).
The art styles are energetic and fun, the stories range from mundane to quirky, the translations are a bit awkward in places and the re-lettering in English is unrestrained and lively. The end result is an enjoyable humour compilation which made a refreshing change from the UK comics of the time.
Here's a few selected pages from the book. I hope you enjoy them...
UPDATE: My thanks to Ruth Bernárdez for identifying the artists of the strips. Ruth writes:
The New Job is By Manuel Vazquez. This, I believe, is from a long series called La Familia Cebolleta (the Cebolleta Family (cebolleta translate to english as Spring Onion, or Scallion).
Zippy and Zappy (Zipi y Zape) are by Escobar. A genius cartoonist sadly gone.
Yolande is by Nebot.
I'm trying to think what Ben Bore was called in Spain but can't remember now. The artist is RAF.
Swindle and co is by Rojas de la Cámara.