Eagle Annual query

I've had a note from Sid Crawford who recalls a story from Eagle Annual that I can't identify (the curse of the "stuff still in boxes" strikes again):

"I remember a short strip in the Eagle annual, about two boys, one of whom was adopted. The story line was that the parents took their own son on a day out but the foster son was adopted for the day by a wealthy family with a wonderful car who took him on a day out where they treated him like a king.

"The punchline was always the return of the "family" and the chagrin of the natural son who had fared worse than his sibling."

Anyone know the name of the strip or story?