It was a middle-grade reader, I think. Kind of goofy and spooky, with monsters and toys that came alive. I specifically remember some army men coming alive to fight a monster. Pretty sure the protagonists were two siblings, a girl and a boy.
Any ideas? I wish I could remember more, I listened to it as an audiobook in the 90’s or 2000’s in the US, I’m pretty sure it was new-ish then so maybe published in the 80’s or sooner?
None of those are what I’m thinking of, although Castle in the Attic was another favorite of mine around that time. : )
Oh man I forgot about that book. Should look it up.