I found the Follyfoot books initially less enjoyable than the tv series as a child for the same reasons as Suzy - Dora was chunky and not pretty, Steve wasn't Steve but Paul and Callie played a much bigger part in the books, when to my mind Dora should have been the lead character and Callie a minor part. But... Monica Dickens' writing style worked its magic on me. She was a very engaging writer, using the second person to draw the readers in and make them feel part of the book. In her Follyfoot series it's a crueller world than the tv show, particularly with Cobbler's Dream, which is certainly adult/young adult rather than children's' fiction. The subsequent books in the series tamed down the violence and cruelty somewhat, but the writing style was the same - engaging, with beautiful bursts of humour, and best of all the books don't treat the readers as children in terms of vocabulary or character development. I was eleven when I first read the books but had a much older reading age, and compared to many of the kiddie books in the school library Follyfoot was a revelation (other standouts were K M Peyton's books including the Flambards series).
The younger characters - Dora, Paul/Steve, Ron - were older teens/young adults; although Ron's age isn't mentioned it's assumed he's under 21. Callie was about thirteen in the books. They all had a freedom and independence I envied, and this is true as well of the Fielding family in the World's End series.
Both the Follyfoot and World's End series use financial struggle in the plot lines. The protagonists are poorly off, the Captain/Colonel struggling to keep Follyfoot going, the Fieldings fighting to keep World's End to themselves while their parents are away, and not have their awful uncle and aunt take over. In both series the least likeable people are rich; in fact the wealthier ones behave appallingly towards their animals! I used to cheer when the 'bad guys' got their comeuppance.
I still love re-reading the Follyfoot and World's End series now, almost forty years later. It's like catching up with old friends.