ABANDONED. dark childhood book, two traumatised siblings with bad home life, time travel to parents honeymoon

[Olivia]

I've been looking for this book and its author for ages. I think the author is mainly a children's author, older children but not quite YA. It's very dark, most of the author's books have quite dark/bizarre themes. This one is about two very damaged siblings, one of which always wears the collar of his jumper over his mouth and never speaks. The reason they are so damaged is because their parents spend every living moment screaming at each other and it's always been that way ever since they were very little. At one point they managed to magic themselves back in time (possibly through a keyhole?? seems to be ringing a bell but not sure) and they end up on the beach where their parents spent their honeymoon and they try to work out what went wrong and how to stop them from hating each other as they get older. That's all I can remember but I loved this book and others by the same author and cannot find them anywhere!! please help!

[Lobstergirl, au gratin]

When did you read it? Author female or male? Remember the cover?

[Olivia]

Lobstergirl wrote: "When did you read it? Author female or male? Remember the cover?"

I read in when I was in primary school, so around 2003/2004?? I'm 90% sure the author was male and the cover was black with some kind of design in the middle?

[Lobstergirl, au gratin]

Olivia left the group. Moving to Abandoned.