It's really hard to find anything out about old Kids' Book series. Literally thousands of new ones come out every year and then vanish after a few years. I was talking once with a guy running a huge warehouse-sized, used bookstore in San Diego that specialised in kids' books. He said that one of the main reasons that people came to his place was to try and dig up copies of some obscure book from their childhood.

The one that haunts me is this one about an elephant (not Barbar) who lives with some pals in a Glorminghast-like castle. They travel around by punching numbers into the control panel of a giant mechanical hand that then throws them into a net at their destination. In the book they are puzzled by two towers labelled, respectively "Treac" and "le vat": which of course eventually turns out to be a giant treacle repository.