I did part time as office floater when I first went back to to work.. I was a supervisor before I left, but was happy to go back to a different roll. It was the same industry, just not a permanent role..

I now job share and work 2 days a week for a different company. So between me and the other girl, we have a full time roll in the job we like, just with the more suited hrs.

ETA - answer to your question.. You know your role. Think about if and how it can be split to work part time. What is happening now? Is someone covering it or was it divvied between other staff for the duration of your leave? If you can sell it to your boss, he may suprise you.. But if you think he is going to be reluctant, do some of the thinking for him.