Thought I would start a resource thread we could all add to:
The Out Of Sync Child: Brilliant resource that goes into depth regarding sensory processing disorders
Your Child Is Not Broken: Funny and comforting anecdotes on how to navigate having a child with autism.
Hanen 'More Than Words' is considered the bible for many for ASD children with communication difficulties. Finding the actual book is tricky and expensive - check places like Vinted and Marketplace. I have also seen it on Kindle.