Haha OP if you'd gone back I could get you to find the policy for me!

My boss is great. He knows that I'm struggling with what to do and has been very understanding in all of our conversations while i've been gone. He's even looking for other positions that would suit me better, but considering what I do and where I am that seems unlikely. He's working hard to make the job suit me, rather than just saying no, you have to come back to the role as it was, full time.

You're probably right that I should discuss it with him though. At least then if it turns out that I do leave he won't be surprised and we'll both be prepared for all options.