The Boggart Book

The boggart has lived in a decayed Scottish castle for centuries, making harmless mischief and shapeshifting into different forms. But when the elderly caretaker dies, the castle is inherited by the Volnik family, modern Canadians who don't know about the boggart. They arrive in Scotland to check out their rather decrepit property; the boggart decides to take a nap inside a desk... right before the desk is shipped back to Canada.
A few references to The Loch Ness Monster, maybe not as good as the Archie Wilson Loch Ness books but still good. The age target was a little weird as some point I thought it was for 8 year olds and then it has some complicated chapters, I'm 14 and found hard to follow. Still a good read.