Secret of the Tower

From Author Wars - https://authorwars.com/publications/secret-of-the-tower-270533.html

Overview:

Title: Secret of the Tower
Author: Debra Doyle, James D. Macdonald
Year: 2003
ISBN-10: 0733616909
Publisher: Hodder Headline Australia
Price: A$
Pages: 134
Binding: Trade Paperback
Type: Novel
Title Reference: Secret of the Tower
Notes: No printed price.
The illustrations aren't specifically credited, but they are the same as in the original 1990 Troll edition (Tournament and Tower).