Congrats in the live litter!
But in rabbits, that color is not called tortoisehell; it's called harlequin, Are you sure she's a Lionhead? I can't see a mane in that picture.
31 days is typical, but it can vary.. Most does kindle on day 31 or 32. A doe with a large litter may go as early as day 28 or 29; I had one kindle on day 27 and the babies survived. Does carrying only one or two may go to day 34 or 35; in those cases, the kits are usually so large and the birth process takes so long, they don't survive.