Please help me track down this children's book! I have no idea of the author or title! All I can remember is:
It was set in the modern day (at the time!), which I guess was the late 80s/early 90s. There were 4 children, I think, 2 boys and 2 girls. Probably preteens. Their horrible neighbour owned a farm with a beautiful wildlife pond. For some reason he's planning to fill it in. The children know this will be detrimental to all the wildlife so they plan to stop it. He has a beautiful young fiancée, Prunella, who's actually not bad, and they work together to convince her to break up with him I think? The baddie farmer has/had a dad who was even worse than him. When he was a little boy his dad used to do psychopathic things like making him ride on a mad bull, and drowning kittens.
It's really bothering me now!! Ringing any bells with anyone?