Possibly - you may benefit from the CLI upgrader for this reason (though I wouldn't flip to it right now). Though I don't think step 10 is a particular huge step. Refreshing should let it pick up from where it left off.
Thanks Mike. I stopped and refreshed the page and it immediately skipped through to 11. Took a while to get all the way through, but it's fine. It had previously run ok on our /sandbox which has, in theory, the same database, so I was confused as to why the /community install had slowed up.
By the way we decided to run our new editorial site through Xenforo, which slowed up development a while, but is a good investment in the long run.