I know all variations are considered on own merit, but what do you think the chances are, someone wants me to have 8 month old for about 12 weeks 1 day a week, I have no other children that day except Grace who's 6 weeks

To be honest I'm not sure, ofsted don't usually allow variations for new starters unless it's for siblings. Worth asking though! Good luck.

they are not keen on giving variations to new starters usually only for continuaty f care. worth a try thought, nothing to loose